Inboard spring arrangement for a clutch actuated differential

ABSTRACT

The present disclosure relates to a differential including a differential case adapted to be rotated about an axis of rotation. The differential also includes a cross-shaft operatively coupled to the differential case such that the cross-shaft and the differential case rotate together about the axis of rotation; left and right clutch actuators having opposing inboard sides between which the cross-shaft is positioned; and left and right axle hubs positioned on opposite sides of the cross-shaft. A left clutch pack prevents relative rotation between the left clutch actuator and the left axle hub about the axis of rotation when a left clutch engagement pressure is applied to the left clutch pack and a right clutch pack prevents relative rotation between the right clutch actuator and the right axle hub about the axis of rotation when a right clutch engagement pressure is applied to the right clutch pack. A clutch pre-load spring applies pressure to both the left and right clutch packs without applying pressure to the left and right clutch actuators. The clutch pre-load spring is positioned inboard of the left and right clutch packs. Contact between the cross-shaft and a ramp surface at the inboard side of the left clutch actuator causes the left clutch engagement pressure to be applied to the left clutch pack, and contact between the cross-shaft and a ramp surface at the inboard side of the right clutch actuator causes the right clutch engagement pressure to be applied to the right clutch pack.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to U.S. Provisional PatentApplication No. 61/784,560, filed Mar. 14, 2013, U.S. Provisional PatentApplication No. 61/784,595, filed Mar. 14, 2013, U.S. Provisional PatentApplication No. 61/784,637, filed Mar. 14, 2013, and U.S. ProvisionalPatent Application No. 61/784,672, filed Mar. 14, 2013. The disclosuresof each of those applications are hereby incorporated by reference intheir entireties.

TECHNICAL FIELD

The present disclosure relates generally to differentials configured totransfer torque to first and second axle shafts of an axle assemblywhile concurrently allowing for differential rotation between first andsecond axle shafts.

BACKGROUND

A differential is a component of an axle assembly that is used totransfer torque from a driveshaft to a pair of output shafts (e.g., axleshafts). The driveshaft can be part of a drivetrain powered by a primemover (e.g., an engine, a motor, etc.). The driveshaft can drive thedifferential through the use of a drive gear that meshes with an outergear mounted at the outside of a housing of the differential. Invehicular applications, the differential allows the wheels (e.g., tires)mounted at opposite ends of an axle assembly to rotate at differentspeeds. This is important when a vehicle is turning because the outerwheel travels over an arc of greater distance than the inner wheel.Thus, the outer wheel must rotate at a faster speed than the inner wheelto compensate for the greater distance of travel. The differentialincludes a torque transfer arrangement that allows torque to betransferred from the driveshaft to axle shafts of the axle assemblywhile concurrently allowing the axle shafts to rotate at differentspeeds as needed. Two example types of differentials include bevel-styledifferentials and so called “gearless” differentials.

Bevel-style differentials include a differential case that is rotatedabout an axis of rotation by a driveshaft. The driveshaft can be poweredby a prime mover of a vehicle. A gear interface can be used to transfertorque from the driveshaft to the differential case. First and secondside bevel gears are mounted within the differential case. The first andsecond bevel gears are coaxially aligned along the axis of rotation ofthe differential case and are coupled to axle shafts of an axleassembly. The axle shafts extend through co-axially aligned openingsdefined by the differential case that are aligned with the axis ofrotation of the differential case. An array of pinion bevel gears ismounted within the differential case between the first and second sidebevel gears. The pinion bevel gears are rotatably mounted on gear shaftscarried with the differential case. The array of pinion bevel gearsintermesh with the first and second side bevel gears to form a torquetransfer arrangement configured for transferring torque between thepinion bevel gears and the first and second side gears and for allowingthe first and second side bevel gears and their corresponding axleshafts to rotate at different rotational speeds with respect to oneanother.

Similar to a bevel-style differential, a gearless differential includesa differential case that is rotated about an axis of rotation by adriveshaft. A gear interface can be used to transfer torque from thedriveshaft to the differential case. The differential case definesco-axially aligned openings aligned along the axis of rotation of thedifferential case. The co-axially aligned openings receive axle shaftsof an axle assembly. Unlike a bevel-style differential, a gearlessdifferential does not include intermeshing gears within the differentialcase for differentially transferring torque from the differential caseto the axle shafts. Instead, gearless differentials include clutcheswithin the differential case for serving this purpose. During normalstraight driving conditions, the clutches are engaged (i.e., actuated)such that torque is transferred from the differential case to both axleshafts. During a turn, the clutch corresponding to the outside wheeldisengages to allow the outside wheel to rotate faster than the insidewheel. Examples of gearless differentials of the type described aboveare disclosed by U.S. Pat. Nos. 4,498,355; 5,413,015; 5,715,733;5,727,430; 6,688,194; 7,874,954; and 8,146,458.

SUMMARY

One aspect of the present disclosure relates to a differential includinga differential case adapted to be rotated about an axis of rotation anda cross-shaft operatively coupled to the differential case such that thecross-shaft and the differential case rotate together about the axis ofrotation. The differential includes left and right clutch actuators thathave opposing inboard sides between which the cross-shaft is positionedand left and right axle hubs that are positioned on opposite sides ofthe cross-shaft. The differential includes a left clutch pack thatprevents relative rotation between the left clutch actuator and the leftaxle hub about the axis of rotation when a left clutch engagementpressure is applied to the left clutch pack. The differential alsoincludes a right clutch pack that prevents relative rotation between theright clutch actuator and the right axle hub about the axis of rotationwhen a right clutch engagement pressure is applied to the right clutchpack. The differential further includes a clutch pre-load spring thatapplies pressure to both the left and right clutch packs withoutapplying pressure to the left and right clutch actuators. The clutchpre-load spring can be positioned inboard of the left and right clutchpacks. Contact between the cross-shaft and a ramp surface at the inboardside of the left clutch actuator causes the left clutch engagementpressure to be applied to the left clutch pack. Contact between thecross-shaft and a ramp surface at the inboard side of the right clutchactuator causes the right clutch engagement pressure to be applied tothe right clutch pack.

Another aspect of the present disclosure relates to a differentialincluding a differential case adapted to be rotated about an axis ofrotation and a cross-shaft operatively coupled to the differential casesuch that the cross-shaft and the differential case rotate togetherabout the axis of rotation. The cross-shaft can be transversely alignedrelative to the axis of rotation. The differential also includes leftand right clutch actuators that have opposing inboard sides betweenwhich the cross-shaft is positioned. The inboard sides of the left andright clutch actuators define pockets that cooperate to define a shaftreceptacle that receives the cross-shaft. Each pocket can include firstand second ramp surfaces separated by a neutral position. The left andright clutch actuators can define spring through-holes each having openinboard and outboard ends. The differential further includes left andright axle hubs that can be positioned on opposite sides of thecross-shaft and a left clutch pack that prevents relative rotationbetween the left clutch actuator and the left axle hub about the axis ofrotation when a left clutch engagement pressure is applied to the leftclutch pack. The differential has a right clutch pack that preventsrelative rotation between the right clutch actuator and the right axlehub about the axis of rotation when a right clutch engagement pressureis applied to the right clutch pack. The differential has clutchpre-load springs that each applies pre-load pressure to both the leftand right clutch packs. The clutch pre-load springs can be positionedinboard of the left and right clutch packs. The clutch pre-load springscan have left portions positioned in the spring through-holes of theleft clutch actuator and right portions positioned in the spring throughholes of the right clutch actuator. The clutch pre-load springs canextend across an interface between the left and right clutch actuators.Contact between the cross-shaft and one of the first and second rampsurfaces of the left clutch actuator causes the left clutch engagementpressure to be applied to the left clutch pack. Contact between thecross-shaft and one of the first and second ramp surfaces of the rightclutch actuator causes the right clutch engagement pressure to beapplied to the right clutch pack. The left engagement pressure is notapplied to the left clutch pack when the cross-shaft aligns with theneutral position of the left clutch actuator. The right engagementpressure is not applied to the right clutch pack when the cross-shaftaligns with the neutral position of the right clutch actuator.

Another aspect of the present disclosure relates to a differentialincluding a differential case adapted to be rotated about an axis ofrotation and a cross-shaft operatively coupled to the differential casesuch that the cross-shaft and the differential case rotate togetherabout the axis of rotation. The cross-shaft can be transversely alignedrelative to the axis of rotation. The differential includes left andright clutch housings that have opposing inboard sides between which thecross-shaft is positioned. The inboard sides of the left and rightclutch housings define pockets that cooperate to define a shaftreceptacle that receives the cross-shaft and each pocket includes firstand second ramp surfaces that are angled relative to one another so asto converge toward a neutral position located between the first andsecond ramp surfaces. The left and right clutch housings define springthrough-holes each having open inboard and outboard ends. Thedifferential includes left and right axle hubs positioned on oppositesides of the cross-shaft. The left and right axle hubs can be co-axiallyaligned along the axis of rotation. The differential has a left clutchpack that is housed at least partially within the left clutch housingand a right clutch pack that is housed at least partially within theright clutch housing. The left and right clutch packs each include firstclutch plates that are interleaved within respect to second clutchplates. The first clutch plates of the left clutch pack are carried withthe left clutch housing and the second clutch plates of the left clutchpack are carried with the left axle hub. Relative rotation about theaxis of rotation is prevented between the left clutch housing and theleft axle hub when a left clutch engagement pressure is applied to theleft clutch pack. Relative rotation about the axis of rotation ispermitted between the left clutch housing and the left axle hub whenonly a left clutch pre-load pressure is applied to the left clutch pack.The first clutch plates of the right clutch pack are carried with theright clutch housing and the second clutch plates of the right clutchpack are carried with the right axle hub. Relative rotation about theaxis of rotation is prevented between the right clutch housing and theright axle hub when a right clutch engagement pressure is applied to theright clutch pack. Relative rotation about the axis of rotation ispermitted between the right clutch housing and the right axle hub whenonly a right clutch pre-load pressure is applied to the right clutchpack. The differential further includes a plurality of clutch pre-loadsprings that cooperate to apply the left and right pre-load pressures tothe left and right clutch packs. The clutch pre-load springs can bepositioned inboard of the left and right clutch packs and each have aleft portion positioned within one of the spring through-holes of theleft clutch housing and a right portion positioned within one of thespring through-holes of the right clutch housing. Each of the clutchpre-load springs can be configured to apply a portion of the leftpre-load pressure to the left clutch pack and a portion of the rightpre-load pressure to the right clutch pack. Contact between thecross-shaft and one of the first and second ramp surfaces of the leftclutch housing causes the left clutch engagement pressure to be appliedto the left clutch pack. Contact between the cross-shaft and one of thefirst and second ramp surfaces of the right clutch housing causes theright clutch engagement pressure to be applied to the right clutch pack.The left engagement pressure is not applied to the left clutch pack whenthe cross-shaft aligns with the neutral position of the left clutchhousing. The right engagement pressure is not applied to the rightclutch pack when the cross-shaft aligns with the neutral position of theright clutch housing.

Another aspect of the present disclosure relates to a differentialincluding a differential case adapted to be rotated about an axis ofrotation and a cross-shaft operatively coupled to the differential casesuch that the cross-shaft and the differential case rotate togetherabout the axis of rotation. The differential includes left and rightclutch actuators that have opposing inboard sides between which thecross-shaft is positioned and left and right axle hubs positioned onopposite sides of the cross-shaft. The differential includes a leftclutch pack that prevents relative rotation between the left clutchactuator and the left axle hub about the axis of rotation when a leftclutch engagement pressure is applied to the left clutch pack. Thedifferential includes a right clutch pack that prevents relativerotation between the right clutch actuator and the right axle hub aboutthe axis of rotation when a right clutch engagement pressure is appliedto the right clutch pack. The differential further includes a rotationlimiting arrangement at the inboard sides of the left and right clutchactuators for limiting relative rotation between the left and rightclutch actuators about the axis of rotation. The rotation limitingarrangement includes a limiter captured between first and second stopsurfaces which cooperate to define a limited range of relativerotational movement between the left and right clutch actuators. Thelimiter has a first location that makes line contact with the first stopsurface to stop relative rotation in a first rotational directionbetween the left and right clutch actuators. The limiter has a secondlocation that makes line contact with the second stop surface to stoprelative rotation in a second rotational direction between the left andright clutch actuators. The first rotational direction can be oppositefrom the second rotational direction. Contact between the cross-shaftand a ramp surface at the inboard side of the left clutch actuatorcauses the left clutch engagement pressure to be applied to the leftclutch pack. Contact between the cross-shaft and a ramp surface at theinboard side of the right clutch actuator causes the right clutchengagement pressure to be applied to the right clutch pack.

A further aspect of the present disclosure relates to a differentialincluding a differential case adapted to be rotated about an axis ofrotation and a cross-shaft operatively coupled to the differential casesuch that the cross-shaft and the differential case rotate togetherabout the axis of rotation. The differential includes left and rightclutch actuators that have opposing inboard sides between which thecross-shaft is positioned. The inboard sides of the left and rightclutch actuators define pockets that cooperate to define a shaftreceptacle that receives the cross-shaft and each pocket includes firstand second ramp surfaces that are angled relative to one another so asto converge toward a neutral position positioned between the first andsecond ramp surfaces. The differential has left and right axle hubspositioned on opposite sides of the cross-shaft. The differential has aleft clutch pack that prevents relative rotation between the left clutchactuator and the left axle hub about the axis of rotation when a leftclutch engagement pressure is applied to the left clutch pack. Thedifferential has a right clutch pack that prevents relative rotationbetween the right clutch actuator and the right axle hub about the axisof rotation when a right clutch engagement pressure is applied to theright clutch pack. The differential further includes a rotation limitingarrangement at the inboard sides of the left and right clutch actuatorsfor limiting relative rotation between the left and right clutchactuators about the axis of rotation. The rotation limiting arrangementincludes a post and a post receptacle provided at the inboard side ofeach of the left and right clutch actuators. The post receptacles eachare located between opposing first and second stop surfaces. The post ofthe left clutch actuator is received within the post receptacle of theright clutch actuator and the post of the right clutch actuator isreceived within the post receptacle of the left clutch actuator. Theposts have first curved locations that make line contact with the firststop surfaces to stop relative rotation in a first rotational directionbetween the left and right clutch actuators. The posts have secondcurved locations that makes line contact with the second stop surfacesto stop relative rotation in a second rotational direction between theleft and right clutch actuators. The first rotational direction isopposite from the second rotational direction. Contact between thecross-shaft and the first or second ramp surface at the inboard side ofthe left clutch actuator causes the left clutch engagement pressure tobe applied to the left clutch pack. Contact between the cross-shaft andthe first or second ramp surface at the inboard side of the right clutchactuator causes the right clutch engagement pressure to be applied tothe right clutch pack. The left engagement pressure is not applied tothe left clutch pack when the cross-shaft aligns with the neutralposition of the left clutch actuator. The right engagement pressure isnot applied to the right clutch pack when the cross-shaft aligns withthe neutral position of the right clutch actuator.

A further aspect of the present disclosure relates to a differentialincluding a differential case adapted to be rotated about an axis ofrotation and a cross-shaft operatively coupled to the differential casesuch that the cross-shaft and the differential case rotate togetherabout the axis of rotation. The differential includes left and rightclutch housings that have opposing inboard sides between which thecross-shaft is positioned and left and right axle hubs positioned onopposite sides of the cross-shaft. The differential includes a leftclutch pack positioned within the left clutch housing that preventsrelative rotation between the left clutch housing and the left axle hubabout the axis of rotation when a left clutch engagement pressure isapplied to the left clutch pack. The differential includes a rightclutch pack positioned within the right clutch housing that preventsrelative rotation between the right clutch actuator and the right axlehub about the axis of rotation when a right clutch engagement pressureis applied to the right clutch pack. The left and right clutch packseach include first and second clutch plates that are interleaved withrespect to each other. The first clutch plates interface with the leftand right clutch housings at first spline interfaces and the secondclutch plates interface with left and right axle hubs at second splineinterfaces. The first and second spline interfaces include splines thatfit within spline receptacles. The spline receptacles define transversecross-sectional areas. At least some of the splines include firstsplines that have transverse cross-sectional areas that occupy no morethan 85 percent of the cross-sectional areas of the spline receptaclesin which they are received such that axial oil flow paths are definedwithin the spline receptacles for allowing oil to escape from betweenthe first and second clutch plates when the left and right clutch packsare actuated. Contact between the cross-shaft and a ramp surface at theinboard side of the left clutch actuator causes the left clutchengagement pressure to be applied to the left clutch pack. Contactbetween the cross-shaft and a ramp surface at the inboard side of theright clutch actuator causes the right clutch engagement pressure to beapplied to the right clutch pack.

A further aspect still of the present disclosure relates to adifferential including a differential case adapted to be rotated aboutan axis of rotation. The differential case includes left and right axleshaft openings aligned along the axis of rotation. The differential casedefines an interior including a main inner chamber and left and rightpockets. The left and right pockets are aligned along the axis ofrotation. The differential case further includes a side opening and adifferential torque transfer assembly that includes left and rightclutch actuators having opposing inboard sides between which thecross-shaft is positioned. The differential torque transfer assemblyalso includes left and right axle hubs positioned on opposite sides ofthe cross-shaft. The differential torque transfer assembly has a leftclutch pack that prevents relative rotation between the left clutchactuator and the left axle hub about the axis of rotation when a leftclutch engagement pressure is applied to the left clutch pack. Thedifferential torque transfer assembly further includes a right clutchpack that prevents relative rotation between the right clutch actuatorand the right axle hub about the axis of rotation when a right clutchengagement pressure is applied to the right clutch pack. Contact betweenthe cross-shaft and a ramp surface at the inboard side of the leftclutch actuator causes the left clutch engagement pressure to be appliedto the left clutch pack. Contact between the cross-shaft and a rampsurface at the inboard side of the right clutch actuator causes theright clutch engagement pressure to be applied to the right clutch pack.The differential torque transfer assembly is moveable between an axiallycompressed configuration and an axially extended configuration. Thedifferential torque transfer assembly can be loaded into the interior ofthe differential case through the side opening when the differentialtorque transfer assembly is in the axially compressed configuration. Theleft and right axle hubs respectively fit within the left and rightpockets of the differential case when the differential torque transferassembly is in the axially extended configuration.

Another aspect of the present disclosure relates to a method forinstalling a differential including a differential case and a maintorque transfer assembly. The differential case defines axle shaftopenings that extend along an axis of the differential case. The maintorque transfer assembly includes left and right clutch actuators, leftand right axle hubs, and left and right clutches that control relativerotation between the left and right clutch actuators and the left andright axle hubs respectively. The method includes the steps of insertingthe main torque transfer assembly into the differential case through aside opening defined by the differential case and expanding the maintorque transfer assembly along the axis of the differential case afterthe main torque transfer assembly has been inserted into thedifferential case through the side opening.

Another aspect of the present disclosure relates to a differentialincluding a differential case adapted to be rotated about an axis ofrotation and a cross-shaft operatively coupled to the differential casesuch that the cross-shaft and the differential case rotate togetherabout the axis of rotation. The differential includes left and rightclutch actuators that have opposing inboard sides between which thecross-shaft is positioned. The differential includes left and right axlehubs positioned on opposite sides of the cross-shaft. The differentialfurther includes a left clutch pack that prevents relative rotationbetween the left clutch actuator and the left axle hub about the axis ofrotation when a left clutch engagement pressure is applied to the leftclutch pack. The differential also includes a right clutch pack thatprevents relative rotation between the right clutch actuator and theright axle hub about the axis of rotation when a right clutch engagementpressure is applied to the right clutch pack. The differential has afirst spring arrangement that applies a left clutch pre-load to the leftclutch pack and a right clutch pre-load to the right clutch pack and asecond spring arrangement that biases the left and right clutchactuators toward one another. The second spring arrangement includes atleast one coil spring and is configured to not transfer spring pressurethrough the left and right clutch packs. Contact between the cross-shaftand a ramp surface at the inboard side of the left clutch actuatorcauses the left clutch engagement pressure to be applied to the leftclutch pack. Contact between the cross-shaft and a ramp surface at theinboard side of the right clutch actuator causes the right clutchengagement pressure to be applied to the right clutch pack.

Another aspect of the present disclosure relates to a differentialincluding a differential case adapted to be rotated about an axis ofrotation and a cross-shaft operatively coupled to the differential casesuch that the cross-shaft and the differential case rotate togetherabout the axis of rotation. The cross-shaft can be transversely alignedrelative to the axis of rotation. The differential includes left andright clutch housings that have opposing inboard sides between which thecross-shaft is positioned. The inboard sides of the left and rightclutch housings define pockets that cooperate to define a shaftreceptacle that receives the cross-shaft and each pocket includes firstand second ramp surfaces that are angled relative to one another so asto converge toward a neutral position located between the first andsecond ramp surfaces. The differential further includes left and rightaxle hubs positioned on opposite sides of the cross-shaft. The left andright axle hubs are co-axially aligned along the axis of rotation. Thedifferential has a left clutch pack housed at least partially within theleft clutch housing and a right clutch pack that is housed at leastpartially within the right clutch housing. The left and right clutchpacks each include first clutch plates that are interleaved withinrespect to second clutch plates. The first clutch plates of the leftclutch pack are carried with the left clutch housing and the secondclutch plates of the left clutch pack are carried with the left axlehub. Relative rotation about the axis of rotation is prevented betweenthe left clutch housing and the left axle hub when a left clutchengagement pressure is applied to the left clutch pack. Relativerotation about the axis of rotation is permitted between the left clutchhousing and the left axle hub when the left clutch engagement pressureis not applied to the left clutch pack. The first clutch plates of theright clutch pack are carried with the right clutch housing and thesecond clutch plates of the right clutch pack are carried with the rightaxle hub. Relative rotation about the axis of rotation is preventedbetween the right clutch housing and the right axle hub when a rightclutch engagement pressure is applied to the right clutch pack. Relativerotation about the axis of rotation is permitted between the rightclutch housing and the right axle hub when the right clutch engagementpressure is not applied to the right clutch pack. The differential alsoincludes left and right outboard coil springs that bias the left andright clutch housings toward one another and against the cross-shaft.The left and right outboard springs can be configured to not transferspring pressure through the left and right clutch packs. Contact betweenthe cross-shaft and one of the first and second ramp surfaces of theleft clutch housing causes the left clutch engagement pressure to beapplied to the left clutch pack. Contact between the cross-shaft and oneof the first and second ramp surfaces of the right clutch housing causesthe right clutch engagement pressure to be applied to the right clutchpack. The left engagement pressure is not applied to the left clutchpack when the cross-shaft aligns with the neutral position of the leftclutch housing. The right engagement pressure is not applied to theright clutch pack when the cross-shaft aligns with the neutral positionof the right clutch housing.

A further aspect of the present disclosure relates to a differentialincluding a differential case adapted to be rotated about an axis ofrotation and a cross-shaft operatively coupled to the differential casesuch that the cross-shaft and the differential case rotate togetherabout the axis of rotation. The differential includes left and rightclutch actuators that have opposing inboard sides between which thecross-shaft is positioned. The inboard sides of the left and rightclutch actuators define pockets that cooperate to define a shaftreceptacle that receives the cross-shaft and each pocket includes firstand second ramp surfaces that are angled relative to one another so asto converge toward a neutral position located between the first andsecond ramp surfaces. The differential also includes left and right axlehubs positioned on opposite sides of the cross-shaft. The differentialhas a left clutch pack that prevents relative rotation between the leftclutch actuator and the left axle hub about the axis of rotation when aleft clutch engagement pressure is applied to the left clutch pack. Thedifferential has a right clutch pack that prevents relative rotationbetween the right clutch actuator and the right axle hub about the axisof rotation when a right clutch engagement pressure is applied to theright clutch pack. The differential includes a spring arrangement thatbiases the left and right clutch actuators toward one another. Contactbetween the cross-shaft and one of the first and second ramp surfaces ofthe left clutch actuator causes the left clutch engagement pressure tobe applied to the left clutch pack. Contact between the cross-shaft andone of the first and second ramp surfaces of the right clutch actuatorcauses the right clutch engagement pressure to be applied to the rightclutch pack. The left engagement pressure is not applied to the leftclutch pack when the cross-shaft aligns with the neutral position of theleft clutch housing. The right engagement pressure is not applied to theright clutch pack when the cross-shaft aligns with the neutral positionof the right clutch housing. The left and right clutch housings eachinclude inner and outer circumferential boundaries that extend aroundthe axis of rotation. The pockets are defined between the inner andouter circumferential boundaries and the pockets include shaft insertionchamfers positioned at the outer circumferential boundaries in alignmentwith the neutral positions.

A further aspect of the present disclosure relates to a differentialincluding a differential case adapted to be rotated about an axis ofrotation and a cross-shaft operatively coupled to the differential casesuch that the cross-shaft and the differential case rotate togetherabout the axis of rotation. The differential includes left and rightclutch actuators that have opposing inboard sides between which thecross-shaft is positioned and left and right axle hubs that arepositioned on opposite sides of the cross-shaft. The differentialincludes a left clutch pack that prevents relative rotation between theleft clutch actuator and the left axle hub about the axis of rotationwhen a left clutch engagement pressure is applied to the left clutchpack. The differential also includes a right clutch pack that preventsrelative rotation between the right clutch actuator and the right axlehub about the axis of rotation when a right clutch engagement pressureis applied to the right clutch pack. The differential further includes aclutch pre-load spring that applies pressure to both the left and rightclutch packs without applying pressure to the left and right clutchactuators. The clutch pre-load spring can be positioned inboard of theleft and right clutch packs. Contact between the cross-shaft and a rampsurface at the inboard side of the left clutch actuator causes the leftclutch engagement pressure to be applied to the left clutch pack.Contact between the cross-shaft and a ramp surface at the inboard sideof the right clutch actuator causes the right clutch engagement pressureto be applied to the right clutch pack. A central reference planeextends along an interface between the inboard sides of the left andright clutch actuators. The central reference plane is perpendicularwith respect to the axis of rotation and the clutch pre-load springextends across the central reference plane.

Another aspect of the present disclosure relates to a differentialincluding a differential case adapted to be rotated about an axis ofrotation and a cross-shaft operatively coupled to the differential casesuch that the cross-shaft and the differential case rotate togetherabout the axis of rotation. The differential includes left and rightclutch actuators that have opposing inboard sides between which thecross-shaft is positioned and left and right axle hubs that arepositioned on opposite sides of the cross-shaft. The differentialincludes a left clutch pack that prevents relative rotation between theleft clutch actuator and the left axle hub about the axis of rotationwhen a left clutch engagement pressure is applied to the left clutchpack. The differential also includes a right clutch pack that preventsrelative rotation between the right clutch actuator and the right axlehub about the axis of rotation when a right clutch engagement pressureis applied to the right clutch pack. The differential further includes aclutch pre-load spring that applies pressure to both the left and rightclutch packs without applying pressure to the left and right clutchactuators. The clutch pre-load spring can be positioned inboard of theleft and right clutch packs. Contact between the cross-shaft and a rampsurface at the inboard side of the left clutch actuator causes the leftclutch engagement pressure to be applied to the left clutch pack.Contact between the cross-shaft and a ramp surface at the inboard sideof the right clutch actuator causes the right clutch engagement pressureto be applied to the right clutch pack. A central reference planeextends along an interface between the inboard sides of the left andright clutch actuators. The central reference plane is perpendicularwith respect to the axis of rotation and the clutch pre-load springextends across the central reference plane. A limited range ofrotational movement about the axis of rotation is permitted between theleft and right clutch actuators. The clutch pre-load spring flexes inresponse to relative rotation between the left and right clutchactuators about the axis of rotation.

Another aspect of the present disclosure relates to a differentialincluding a differential case adapted to be rotated about an axis ofrotation and a cross-shaft operatively coupled to the differential casesuch that the cross-shaft and the differential case rotate togetherabout the axis of rotation. The differential includes left and rightclutch actuators that have opposing inboard sides between which thecross-shaft is positioned and left and right axle hubs that arepositioned on opposite sides of the cross-shaft. The differentialincludes a left clutch pack that prevents relative rotation between theleft clutch actuator and the left axle hub about the axis of rotationwhen a left clutch engagement pressure is applied to the left clutchpack. The differential also includes a right clutch pack that preventsrelative rotation between the right clutch actuator and the right axlehub about the axis of rotation when a right clutch engagement pressureis applied to the right clutch pack. The differential further includes aclutch pre-load spring that applies pressure to both the left and rightclutch packs without applying pressure to the left and right clutchactuators. The clutch pre-load spring can be positioned inboard of theleft and right clutch packs. Contact between the cross-shaft and a rampsurface at the inboard side of the left clutch actuator causes the leftclutch engagement pressure to be applied to the left clutch pack.Contact between the cross-shaft and a ramp surface at the inboard sideof the right clutch actuator causes the right clutch engagement pressureto be applied to the right clutch pack. A central reference planeextends along an interface between the inboard sides of the left andright clutch actuators. The central reference plane is perpendicularwith respect to the axis of rotation and the clutch pre-load springextends across the central reference plane. A limited range ofrotational movement about the axis of rotation is permitted between theleft and right clutch actuators. The clutch pre-load spring flexes inresponse to relative rotation between the left and right clutchactuators about the axis of rotation. The clutch pre-load spring is acoil spring.

A further aspect still of the present disclosure relates to adifferential including a differential case adapted to be rotated aboutan axis of rotation and a cross-shaft operatively coupled to thedifferential case such that the cross-shaft and the differential caserotate together about the axis of rotation. The differential includesleft and right clutch actuators that have opposing inboard sides betweenwhich the cross-shaft is positioned and left and right axle hubs thatare positioned on opposite sides of the cross-shaft. The differentialincludes a left clutch pack that prevents relative rotation between theleft clutch actuator and the left axle hub about the axis of rotationwhen a left clutch engagement pressure is applied to the left clutchpack. The differential also includes a right clutch pack that preventsrelative rotation between the right clutch actuator and the right axlehub about the axis of rotation when a right clutch engagement pressureis applied to the right clutch pack. The differential further includes aclutch pre-load spring that applies pressure to both the left and rightclutch packs without applying pressure to the left and right clutchactuators. The clutch pre-load spring can be positioned inboard of theleft and right clutch packs. Contact between the cross-shaft and a rampsurface at the inboard side of the left clutch actuator causes the leftclutch engagement pressure to be applied to the left clutch pack.Contact between the cross-shaft and a ramp surface at the inboard sideof the right clutch actuator causes the right clutch engagement pressureto be applied to the right clutch pack. A central reference planeextends along an interface between the inboard sides of the left andright clutch actuators. The central reference plane is perpendicularwith respect to the axis of rotation and the clutch pre-load springextends across the central reference plane. A limited range ofrotational movement about the axis of rotation is permitted between theleft and right clutch actuators. The clutch pre-load spring flexes inresponse to relative rotation between the left and right clutchactuators about the axis of rotation. The clutch pre-load spring is acoil spring. The inboard sides of the left and right clutch actuatorsdefine pockets that cooperate to define a shaft receptacle that receivesthe cross-shaft. Each pocket includes first and second ramp surfacesseparated by a neutral position. The left engagement pressure is notapplied to the left clutch pack when the cross-shaft aligns with theneutral position of the left clutch actuator. The right engagementpressure is not applied to the right clutch pack when the cross-shaftaligns with the neutral position of the right clutch actuator.

Another aspect of the present disclosure relates to a differentialincluding a differential case adapted to be rotated about an axis ofrotation and a cross-shaft operatively coupled to the differential casesuch that the cross-shaft and the differential case rotate togetherabout the axis of rotation. The differential includes left and rightclutch actuators that have opposing inboard sides between which thecross-shaft is positioned and left and right axle hubs that arepositioned on opposite sides of the cross-shaft. The differentialincludes a left clutch pack that prevents relative rotation between theleft clutch actuator and the left axle hub about the axis of rotationwhen a left clutch engagement pressure is applied to the left clutchpack. The differential also includes a right clutch pack that preventsrelative rotation between the right clutch actuator and the right axlehub about the axis of rotation when a right clutch engagement pressureis applied to the right clutch pack. The differential further includes aclutch pre-load spring that applies pressure to both the left and rightclutch packs without applying pressure to the left and right clutchactuators. The clutch pre-load spring can be positioned inboard of theleft and right clutch packs. Contact between the cross-shaft and a rampsurface at the inboard side of the left clutch actuator causes the leftclutch engagement pressure to be applied to the left clutch pack.Contact between the cross-shaft and a ramp surface at the inboard sideof the right clutch actuator causes the right clutch engagement pressureto be applied to the right clutch pack. A central reference planeextends along an interface between the inboard sides of the left andright clutch actuators. The central reference plane is perpendicularwith respect to the axis of rotation and the clutch pre-load springextends across the central reference plane. A limited range ofrotational movement about the axis of rotation is permitted between theleft and right clutch actuators. The clutch pre-load spring flexes inresponse to relative rotation between the left and right clutchactuators about the axis of rotation. The clutch pre-load spring is acoil spring. The inboard sides of the left and right clutch actuatorsdefine pockets that cooperate to define a shaft receptacle that receivesthe cross-shaft. Each pocket includes first and second ramp surfacesseparated by a neutral position. The left engagement pressure is notapplied to the left clutch pack when the cross-shaft aligns with theneutral position of the left clutch actuator. The right engagementpressure is not applied to the right clutch pack when the cross-shaftaligns with the neutral position of the right clutch actuator. Thedifferential further includes a plurality of the clutch pre-load springsthat cooperate to apply left and right clutch pre-loads respectively tothe left and right clutch packs. Each of the clutch pre-load springsapplies a portion of the left clutch pre-load and a portion of the rightclutch pre-load and none of the clutch pre-load springs apply pressureto the left and right actuators.

Another aspect of the present disclosure relates to a differentialincluding a differential case adapted to be rotated about an axis ofrotation and a cross-shaft operatively coupled to the differential casesuch that the cross-shaft and the differential case rotate togetherabout the axis of rotation. The differential includes left and rightclutch actuators that have opposing inboard sides between which thecross-shaft is positioned and left and right axle hubs that arepositioned on opposite sides of the cross-shaft. The differentialincludes a left clutch pack that prevents relative rotation between theleft clutch actuator and the left axle hub about the axis of rotationwhen a left clutch engagement pressure is applied to the left clutchpack. The differential also includes a right clutch pack that preventsrelative rotation between the right clutch actuator and the right axlehub about the axis of rotation when a right clutch engagement pressureis applied to the right clutch pack. The differential further includes aclutch pre-load spring that applies pressure to both the left and rightclutch packs without applying pressure to the left and right clutchactuators. The clutch pre-load spring can be positioned inboard of theleft and right clutch packs. Contact between the cross-shaft and a rampsurface at the inboard side of the left clutch actuator causes the leftclutch engagement pressure to be applied to the left clutch pack.Contact between the cross-shaft and a ramp surface at the inboard sideof the right clutch actuator causes the right clutch engagement pressureto be applied to the right clutch pack. A central reference planeextends along an interface between the inboard sides of the left andright clutch actuators. The central reference plane is perpendicularwith respect to the axis of rotation and the clutch pre-load springextends across the central reference plane. A limited range ofrotational movement about the axis of rotation is permitted between theleft and right clutch actuators. The clutch pre-load spring flexes inresponse to relative rotation between the left and right clutchactuators about the axis of rotation. The clutch pre-load spring is acoil spring. The inboard sides of the left and right clutch actuatorsdefine pockets that cooperate to define a shaft receptacle that receivesthe cross-shaft. Each pocket includes first and second ramp surfacesseparated by a neutral position. The left engagement pressure is notapplied to the left clutch pack when the cross-shaft aligns with theneutral position of the left clutch actuator. The right engagementpressure is not applied to the right clutch pack when the cross-shaftaligns with the neutral position of the right clutch actuator. Thedifferential further includes a plurality of the clutch pre-load springsthat cooperate to apply left and right clutch pre-loads respectively tothe left and right clutch packs. Each of the clutch pre-load springsapplies a portion of the left clutch pre-load and a portion of the rightclutch pre-load and none of the clutch pre-load springs apply pressureto the left and right actuators. The clutch pre-load springs are spaceduniformly about the axis of rotation.

Another aspect of the present disclosure relates to a differentialincluding a differential case adapted to be rotated about an axis ofrotation and a cross-shaft operatively coupled to the differential casesuch that the cross-shaft and the differential case rotate togetherabout the axis of rotation. The differential includes left and rightclutch actuators that have opposing inboard sides between which thecross-shaft is positioned and left and right axle hubs that arepositioned on opposite sides of the cross-shaft. The differentialincludes a left clutch pack that prevents relative rotation between theleft clutch actuator and the left axle hub about the axis of rotationwhen a left clutch engagement pressure is applied to the left clutchpack. The differential also includes a right clutch pack that preventsrelative rotation between the right clutch actuator and the right axlehub about the axis of rotation when a right clutch engagement pressureis applied to the right clutch pack. The differential further includes aclutch pre-load spring that applies pressure to both the left and rightclutch packs without applying pressure to the left and right clutchactuators. The clutch pre-load spring can be positioned inboard of theleft and right clutch packs. Contact between the cross-shaft and a rampsurface at the inboard side of the left clutch actuator causes the leftclutch engagement pressure to be applied to the left clutch pack.Contact between the cross-shaft and a ramp surface at the inboard sideof the right clutch actuator causes the right clutch engagement pressureto be applied to the right clutch pack. A central reference planeextends along an interface between the inboard sides of the left andright clutch actuators. The central reference plane is perpendicularwith respect to the axis of rotation and the clutch pre-load springextends across the central reference plane. A limited range ofrotational movement about the axis of rotation is permitted between theleft and right clutch actuators. The clutch pre-load spring flexes inresponse to relative rotation between the left and right clutchactuators about the axis of rotation. The clutch pre-load spring is acoil spring. The inboard sides of the left and right clutch actuatorsdefine pockets that cooperate to define a shaft receptacle that receivesthe cross-shaft. Each pocket includes first and second ramp surfacesseparated by a neutral position. The left engagement pressure is notapplied to the left clutch pack when the cross-shaft aligns with theneutral position of the left clutch actuator. The right engagementpressure is not applied to the right clutch pack when the cross-shaftaligns with the neutral position of the right clutch actuator. Thedifferential further includes a plurality of the clutch pre-load springsthat cooperate to apply left and right clutch pre-loads respectively tothe left and right clutch packs. Each of the clutch pre-load springsapplies a portion of the left clutch pre-load and a portion of the rightclutch pre-load and none of the clutch pre-load springs apply pressureto the left and right actuators. The left and right clutch actuatorsdefine a plurality of spring holes each having open inboard and outboardends. Each of the clutch pre-load springs extend through one of thespring holes of the left clutch actuator and a corresponding one of thespring bores of the right clutch actuator.

Another aspect of the present disclosure relates to a differentialincluding a differential case adapted to be rotated about an axis ofrotation and a cross-shaft operatively coupled to the differential casesuch that the cross-shaft and the differential case rotate togetherabout the axis of rotation. The differential includes left and rightclutch actuators that have opposing inboard sides between which thecross-shaft is positioned and left and right axle hubs that arepositioned on opposite sides of the cross-shaft. The differentialincludes a left clutch pack that prevents relative rotation between theleft clutch actuator and the left axle hub about the axis of rotationwhen a left clutch engagement pressure is applied to the left clutchpack. The differential also includes a right clutch pack that preventsrelative rotation between the right clutch actuator and the right axlehub about the axis of rotation when a right clutch engagement pressureis applied to the right clutch pack. The differential further includes aclutch pre-load spring that applies pressure to both the left and rightclutch packs without applying pressure to the left and right clutchactuators. The clutch pre-load spring can be positioned inboard of theleft and right clutch packs. Contact between the cross-shaft and a rampsurface at the inboard side of the left clutch actuator causes the leftclutch engagement pressure to be applied to the left clutch pack.Contact between the cross-shaft and a ramp surface at the inboard sideof the right clutch actuator causes the right clutch engagement pressureto be applied to the right clutch pack. The deferential further includesa plurality of the clutch pre-load springs that cooperate to apply leftand right clutch pre-loads respectively to the left and right clutchpacks. Each of the clutch pre-load springs applies a portion of the leftclutch pre-load and a portion of the right clutch pre-load withoutapplying the pre-loads through the left and right clutch actuators.

Another aspect of the present disclosure relates to a differentialincluding a differential case adapted to be rotated about an axis ofrotation and a cross-shaft operatively coupled to the differential casesuch that the cross-shaft and the differential case rotate togetherabout the axis of rotation. The differential includes left and rightclutch actuators that have opposing inboard sides between which thecross-shaft is positioned and left and right axle hubs that arepositioned on opposite sides of the cross-shaft. The differentialincludes a left clutch pack that prevents relative rotation between theleft clutch actuator and the left axle hub about the axis of rotationwhen a left clutch engagement pressure is applied to the left clutchpack. The differential also includes a right clutch pack that preventsrelative rotation between the right clutch actuator and the right axlehub about the axis of rotation when a right clutch engagement pressureis applied to the right clutch pack. The differential further includes aclutch pre-load spring that applies pressure to both the left and rightclutch packs without applying pressure to the left and right clutchactuators. The clutch pre-load spring can be positioned inboard of theleft and right clutch packs. Contact between the cross-shaft and a rampsurface at the inboard side of the left clutch actuator causes the leftclutch engagement pressure to be applied to the left clutch pack.Contact between the cross-shaft and a ramp surface at the inboard sideof the right clutch actuator causes the right clutch engagement pressureto be applied to the right clutch pack. The deferential further includesa plurality of the clutch pre-load springs that cooperate to apply leftand right clutch pre-loads respectively to the left and right clutchpacks. Each of the clutch pre-load springs applies a portion of the leftclutch pre-load and a portion of the right clutch pre-load withoutapplying the pre-loads through the left and right clutch actuators. Theclutch pre-load springs are spaced uniformly about the axis of rotation.

One aspect of the present disclosure relates to a differential includinga differential case adapted to be rotated about an axis of rotation anda cross-shaft operatively coupled to the differential case such that thecross-shaft and the differential case rotate together about the axis ofrotation. The differential includes left and right clutch actuators thathave opposing inboard sides between which the cross-shaft is positionedand left and right axle hubs that are positioned on opposite sides ofthe cross-shaft. The differential includes a left clutch pack thatprevents relative rotation between the left clutch actuator and the leftaxle hub about the axis of rotation when a left clutch engagementpressure is applied to the left clutch pack. The differential alsoincludes a right clutch pack that prevents relative rotation between theright clutch actuator and the right axle hub about the axis of rotationwhen a right clutch engagement pressure is applied to the right clutchpack. The differential further includes a clutch pre-load spring thatapplies pressure to both the left and right clutch packs withoutapplying pressure to the left and right clutch actuators. The clutchpre-load spring can be positioned inboard of the left and right clutchpacks. Contact between the cross-shaft and a ramp surface at the inboardside of the left clutch actuator causes the left clutch engagementpressure to be applied to the left clutch pack. Contact between thecross-shaft and a ramp surface at the inboard side of the right clutchactuator causes the right clutch engagement pressure to be applied tothe right clutch pack. The left and right clutch actuators definethrough-holes that receive the clutch pre-load springs.

One aspect of the present disclosure relates to a differential includinga differential case adapted to be rotated about an axis of rotation anda cross-shaft operatively coupled to the differential case such that thecross-shaft and the differential case rotate together about the axis ofrotation. The differential includes left and right clutch actuators thathave opposing inboard sides between which the cross-shaft is positionedand left and right axle hubs that are positioned on opposite sides ofthe cross-shaft. The differential includes a left clutch pack thatprevents relative rotation between the left clutch actuator and the leftaxle hub about the axis of rotation when a left clutch engagementpressure is applied to the left clutch pack. The differential alsoincludes a right clutch pack that prevents relative rotation between theright clutch actuator and the right axle hub about the axis of rotationwhen a right clutch engagement pressure is applied to the right clutchpack. The differential further includes a clutch pre-load spring thatapplies pressure to both the left and right clutch packs withoutapplying pressure to the left and right clutch actuators. The clutchpre-load spring can be positioned inboard of the left and right clutchpacks. Contact between the cross-shaft and a ramp surface at the inboardside of the left clutch actuator causes the left clutch engagementpressure to be applied to the left clutch pack. Contact between thecross-shaft and a ramp surface at the inboard side of the right clutchactuator causes the right clutch engagement pressure to be applied tothe right clutch pack. The left and right clutch actuators definethrough-holes that receive the clutch pre-load springs. Thethrough-holes each include cylindrical portions and tapered portions andthe tapered portions define diameters that increase in size as thetapered portions extend in an inboard direction. Major diameters of thetapered portions are positioned at the inboard sides of the left andright clutch actuators.

Another aspect of the present disclosure relates to a differentialincluding a differential case adapted to be rotated about an axis ofrotation and a cross-shaft operatively coupled to the differential casesuch that the cross-shaft and the differential case rotate togetherabout the axis of rotation. The differential includes left and rightclutch actuators that have opposing inboard sides between which thecross-shaft is positioned and left and right axle hubs that arepositioned on opposite sides of the cross-shaft. The differentialincludes a left clutch pack that prevents relative rotation between theleft clutch actuator and the left axle hub about the axis of rotationwhen a left clutch engagement pressure is applied to the left clutchpack. The differential also includes a right clutch pack that preventsrelative rotation between the right clutch actuator and the right axlehub about the axis of rotation when a right clutch engagement pressureis applied to the right clutch pack. The differential further includes aclutch pre-load spring that applies pressure to both the left and rightclutch packs without applying pressure to the left and right clutchactuators. The clutch pre-load spring can be positioned inboard of theleft and right clutch packs. Contact between the cross-shaft and a rampsurface at the inboard side of the left clutch actuator causes the leftclutch engagement pressure to be applied to the left clutch pack.Contact between the cross-shaft and a ramp surface at the inboard sideof the right clutch actuator causes the right clutch engagement pressureto be applied to the right clutch pack. The differential furtherincluding a plurality of the clutch pre-load springs that cooperate toapply left and right clutch pre-loads respectively to the left and rightclutch packs. Each of the clutch pre-load springs applies a portion ofthe left clutch pre-load and a portion of the right clutch pre-loadwithout applying the pre-loads through the left and right clutchactuators. The left and right clutch actuators respectively house theleft and right clutch packs. The clutch pre-load springs extend throughthe left and right clutch actuators and across an interface between theleft and right clutch actuators and each of the clutch pre-load springsincludes opposite ends that abut against inboard thrust washers of theleft and right clutch packs.

A further aspect of the present disclosure relates to a differentialincluding a differential case adapted to be rotated about an axis ofrotation and a cross-shaft operatively coupled to the differential casesuch that the cross-shaft and the differential case rotate togetherabout the axis of rotation. The differential includes left and rightclutch actuators that have opposing inboard sides between which thecross-shaft is positioned and left and right axle hubs that arepositioned on opposite sides of the cross-shaft. The differentialincludes a left clutch pack that prevents relative rotation between theleft clutch actuator and the left axle hub about the axis of rotationwhen a left clutch engagement pressure is applied to the left clutchpack. The differential also includes a right clutch pack that preventsrelative rotation between the right clutch actuator and the right axlehub about the axis of rotation when a right clutch engagement pressureis applied to the right clutch pack. The differential further includes aclutch pre-load spring that applies pressure to both the left and rightclutch packs without applying pressure to the left and right clutchactuators. The clutch pre-load spring can be positioned inboard of theleft and right clutch packs. Contact between the cross-shaft and a rampsurface at the inboard side of the left clutch actuator causes the leftclutch engagement pressure to be applied to the left clutch pack.Contact between the cross-shaft and a ramp surface at the inboard sideof the right clutch actuator causes the right clutch engagement pressureto be applied to the right clutch pack. The differential furtherincludes outboard springs that bias the left and right clutch actuatorstoward one another without applying spring load through the left andright clutch packs.

Another aspect of the present disclosure relates to a differentialincluding a differential case adapted to be rotated about an axis ofrotation and a cross-shaft operatively coupled to the differential casesuch that the cross-shaft and the differential case rotate togetherabout the axis of rotation. The cross-shaft can be transversely alignedrelative to the axis of rotation. The differential also includes leftand right clutch actuators that have opposing inboard sides betweenwhich the cross-shaft is positioned. The inboard sides of the left andright clutch actuators define pockets that cooperate to define a shaftreceptacle that receives the cross-shaft. Each pocket can include firstand second ramp surfaces separated by a neutral position. The left andright clutch actuators can define spring through-holes each having openinboard and outboard ends. The differential further includes left andright axle hubs that can be positioned on opposite sides of thecross-shaft and a left clutch pack that prevents relative rotationbetween the left clutch actuator and the left axle hub about the axis ofrotation when a left clutch engagement pressure is applied to the leftclutch pack. The differential has a right clutch pack that preventsrelative rotation between the right clutch actuator and the right axlehub about the axis of rotation when a right clutch engagement pressureis applied to the right clutch pack. The differential has clutchpre-load springs that each applies pre-load pressure to both the leftand right clutch packs. The clutch pre-load springs can be positionedinboard of the left and right clutch packs. The clutch pre-load springscan have left portions positioned in the spring through-holes of theleft clutch actuator and right portions positioned in the spring throughholes of the right clutch actuator. The clutch pre-load springs canextend across an interface between the left and right clutch actuators.Contact between the cross-shaft and one of the first and second rampsurfaces of the left clutch actuator causes the left clutch engagementpressure to be applied to the left clutch pack. Contact between thecross-shaft and one of the first and second ramp surfaces of the rightclutch actuator causes the right clutch engagement pressure to beapplied to the right clutch pack. The left engagement pressure is notapplied to the left clutch pack when the cross-shaft aligns with theneutral position of the left clutch actuator. The right engagementpressure is not applied to the right clutch pack when the cross-shaftaligns with the neutral position of the right clutch actuator. Thespring through-holes each have cylindrical portions adjacent theoutboard ends and tapered portions adjacent the inboard ends. Thetapered portions have major diameters at the inboard sides of the leftand right clutch actuators.

Another aspect of the present disclosure relates to a differentialincluding a differential case adapted to be rotated about an axis ofrotation and a cross-shaft operatively coupled to the differential casesuch that the cross-shaft and the differential case rotate togetherabout the axis of rotation. The cross-shaft can be transversely alignedrelative to the axis of rotation. The differential also includes leftand right clutch actuators that have opposing inboard sides betweenwhich the cross-shaft is positioned. The inboard sides of the left andright clutch actuators define pockets that cooperate to define a shaftreceptacle that receives the cross-shaft. Each pocket can include firstand second ramp surfaces separated by a neutral position. The left andright clutch actuators can define spring through-holes each having openinboard and outboard ends. The differential further includes left andright axle hubs that can be positioned on opposite sides of thecross-shaft and a left clutch pack that prevents relative rotationbetween the left clutch actuator and the left axle hub about the axis ofrotation when a left clutch engagement pressure is applied to the leftclutch pack. The differential has a right clutch pack that preventsrelative rotation between the right clutch actuator and the right axlehub about the axis of rotation when a right clutch engagement pressureis applied to the right clutch pack. The differential has clutchpre-load springs that each applies pre-load pressure to both the leftand right clutch packs. The clutch pre-load springs can be positionedinboard of the left and right clutch packs. The clutch pre-load springscan have left portions positioned in the spring through-holes of theleft clutch actuator and right portions positioned in the spring throughholes of the right clutch actuator. The clutch pre-load springs canextend across an interface between the left and right clutch actuators.Contact between the cross-shaft and one of the first and second rampsurfaces of the left clutch actuator causes the left clutch engagementpressure to be applied to the left clutch pack. Contact between thecross-shaft and one of the first and second ramp surfaces of the rightclutch actuator causes the right clutch engagement pressure to beapplied to the right clutch pack. The left engagement pressure is notapplied to the left clutch pack when the cross-shaft aligns with theneutral position of the left clutch actuator. The right engagementpressure is not applied to the right clutch pack when the cross-shaftaligns with the neutral position of the right clutch actuator. Thespring through-holes each have cylindrical portions adjacent theoutboard ends and tapered portions adjacent the inboard ends. Thetapered portions have major diameters at the inboard sides of the leftand right clutch actuators. The pre-load springs each have opposite endsthat bias against inboard thrust washers of the left and right clutchpacks.

Another aspect of the present disclosure relates to a differentialincluding a differential case adapted to be rotated about an axis ofrotation and a cross-shaft operatively coupled to the differential casesuch that the cross-shaft and the differential case rotate togetherabout the axis of rotation. The cross-shaft can be transversely alignedrelative to the axis of rotation. The differential also includes leftand right clutch actuators that have opposing inboard sides betweenwhich the cross-shaft is positioned. The inboard sides of the left andright clutch actuators define pockets that cooperate to define a shaftreceptacle that receives the cross-shaft. Each pocket can include firstand second ramp surfaces separated by a neutral position. The left andright clutch actuators can define spring through-holes each having openinboard and outboard ends. The differential further includes left andright axle hubs that can be positioned on opposite sides of thecross-shaft and a left clutch pack that prevents relative rotationbetween the left clutch actuator and the left axle hub about the axis ofrotation when a left clutch engagement pressure is applied to the leftclutch pack. The differential has a right clutch pack that preventsrelative rotation between the right clutch actuator and the right axlehub about the axis of rotation when a right clutch engagement pressureis applied to the right clutch pack. The differential has clutchpre-load springs that each applies pre-load pressure to both the leftand right clutch packs. The clutch pre-load springs can be positionedinboard of the left and right clutch packs. The clutch pre-load springscan have left portions positioned in the spring through-holes of theleft clutch actuator and right portions positioned in the spring throughholes of the right clutch actuator. The clutch pre-load springs canextend across an interface between the left and right clutch actuators.Contact between the cross-shaft and one of the first and second rampsurfaces of the left clutch actuator causes the left clutch engagementpressure to be applied to the left clutch pack. Contact between thecross-shaft and one of the first and second ramp surfaces of the rightclutch actuator causes the right clutch engagement pressure to beapplied to the right clutch pack. The left engagement pressure is notapplied to the left clutch pack when the cross-shaft aligns with theneutral position of the left clutch actuator. The right engagementpressure is not applied to the right clutch pack when the cross-shaftaligns with the neutral position of the right clutch actuator. Thedifferential further includes outboard springs that bias the left andright clutch actuators toward one another without applying spring loadthrough the left and right clutch packs.

Another aspect of the present disclosure relates to a differentialincluding a differential case adapted to be rotated about an axis ofrotation and a cross-shaft operatively coupled to the differential casesuch that the cross-shaft and the differential case rotate togetherabout the axis of rotation. The cross-shaft can be transversely alignedrelative to the axis of rotation. The differential includes left andright clutch housings that have opposing inboard sides between which thecross-shaft is positioned. The inboard sides of the left and rightclutch housings define pockets that cooperate to define a shaftreceptacle that receives the cross-shaft and each pocket includes firstand second ramp surfaces that are angled relative to one another so asto converge toward a neutral position located between the first andsecond ramp surfaces. The left and right clutch housings define springthrough-holes each having open inboard and outboard ends. Thedifferential includes left and right axle hubs positioned on oppositesides of the cross-shaft. The left and right axle hubs can be co-axiallyaligned along the axis of rotation. The differential has a left clutchpack that is housed at least partially within the left clutch housingand a right clutch pack that is housed at least partially within theright clutch housing. The left and right clutch packs each include firstclutch plates that are interleaved within respect to second clutchplates. The first clutch plates of the left clutch pack are carried withthe left clutch housing and the second clutch plates of the left clutchpack are carried with the left axle hub. Relative rotation about theaxis of rotation is prevented between the left clutch housing and theleft axle hub when a left clutch engagement pressure is applied to theleft clutch pack. Relative rotation about the axis of rotation ispermitted between the left clutch housing and the left axle hub whenonly a left clutch pre-load pressure is applied to the left clutch pack.The first clutch plates of the right clutch pack are carried with theright clutch housing and the second clutch plates of the right clutchpack are carried with the right axle hub. Relative rotation about theaxis of rotation is prevented between the right clutch housing and theright axle hub when a right clutch engagement pressure is applied to theright clutch pack. Relative rotation about the axis of rotation ispermitted between the right clutch housing and the right axle hub whenonly a right clutch pre-load pressure is applied to the right clutchpack. The differential further includes a plurality of clutch pre-loadsprings that cooperate to apply the left and right pre-load pressures tothe left and right clutch packs. The clutch pre-load springs can bepositioned inboard of the left and right clutch packs and each have aleft portion positioned within one of the spring through-holes of theleft clutch housing and a right portion positioned within one of thespring through-holes of the right clutch housing. Each of the clutchpre-load springs can be configured to apply a portion of the leftpre-load pressure to the left clutch pack and a portion of the rightpre-load pressure to the right clutch pack. Contact between thecross-shaft and one of the first and second ramp surfaces of the leftclutch housing causes the left clutch engagement pressure to be appliedto the left clutch pack. Contact between the cross-shaft and one of thefirst and second ramp surfaces of the right clutch housing causes theright clutch engagement pressure to be applied to the right clutch pack.The left engagement pressure is not applied to the left clutch pack whenthe cross-shaft aligns with the neutral position of the left clutchhousing. The right engagement pressure is not applied to the rightclutch pack when the cross-shaft aligns with the neutral position of theright clutch housing. The spring through-holes each have cylindricalportions adjacent the outboard ends and tapered portions adjacent theinboard ends. The tapered portions have major diameters at the inboardsides of the left and right clutch housings.

Another aspect of the present disclosure relates to a differentialincluding a differential case adapted to be rotated about an axis ofrotation and a cross-shaft operatively coupled to the differential casesuch that the cross-shaft and the differential case rotate togetherabout the axis of rotation. The cross-shaft can be transversely alignedrelative to the axis of rotation. The differential includes left andright clutch housings that have opposing inboard sides between which thecross-shaft is positioned. The inboard sides of the left and rightclutch housings define pockets that cooperate to define a shaftreceptacle that receives the cross-shaft and each pocket includes firstand second ramp surfaces that are angled relative to one another so asto converge toward a neutral position located between the first andsecond ramp surfaces. The left and right clutch housings define springthrough-holes each having open inboard and outboard ends. Thedifferential includes left and right axle hubs positioned on oppositesides of the cross-shaft. The left and right axle hubs can be co-axiallyaligned along the axis of rotation. The differential has a left clutchpack that is housed at least partially within the left clutch housingand a right clutch pack that is housed at least partially within theright clutch housing. The left and right clutch packs each include firstclutch plates that are interleaved within respect to second clutchplates. The first clutch plates of the left clutch pack are carried withthe left clutch housing and the second clutch plates of the left clutchpack are carried with the left axle hub. Relative rotation about theaxis of rotation is prevented between the left clutch housing and theleft axle hub when a left clutch engagement pressure is applied to theleft clutch pack. Relative rotation about the axis of rotation ispermitted between the left clutch housing and the left axle hub whenonly a left clutch pre-load pressure is applied to the left clutch pack.The first clutch plates of the right clutch pack are carried with theright clutch housing and the second clutch plates of the right clutchpack are carried with the right axle hub. Relative rotation about theaxis of rotation is prevented between the right clutch housing and theright axle hub when a right clutch engagement pressure is applied to theright clutch pack. Relative rotation about the axis of rotation ispermitted between the right clutch housing and the right axle hub whenonly a right clutch pre-load pressure is applied to the right clutchpack. The differential further includes a plurality of clutch pre-loadsprings that cooperate to apply the left and right pre-load pressures tothe left and right clutch packs. The clutch pre-load springs can bepositioned inboard of the left and right clutch packs and each have aleft portion positioned within one of the spring through-holes of theleft clutch housing and a right portion positioned within one of thespring through-holes of the right clutch housing. Each of the clutchpre-load springs can be configured to apply a portion of the leftpre-load pressure to the left clutch pack and a portion of the rightpre-load pressure to the right clutch pack. Contact between thecross-shaft and one of the first and second ramp surfaces of the leftclutch housing causes the left clutch engagement pressure to be appliedto the left clutch pack. Contact between the cross-shaft and one of thefirst and second ramp surfaces of the right clutch housing causes theright clutch engagement pressure to be applied to the right clutch pack.The left engagement pressure is not applied to the left clutch pack whenthe cross-shaft aligns with the neutral position of the left clutchhousing. The right engagement pressure is not applied to the rightclutch pack when the cross-shaft aligns with the neutral position of theright clutch housing. The spring through-holes each have cylindricalportions adjacent the outboard ends and tapered portions adjacent theinboard ends. The tapered portions have major diameters at the inboardsides of the left and right clutch housings. The pre-load springs eachhave opposite ends that bias against inboard thrust washers of the leftand right clutch packs.

Another aspect of the present disclosure relates to a differentialincluding a differential case adapted to be rotated about an axis ofrotation and a cross-shaft operatively coupled to the differential casesuch that the cross-shaft and the differential case rotate togetherabout the axis of rotation. The cross-shaft can be transversely alignedrelative to the axis of rotation. The differential includes left andright clutch housings that have opposing inboard sides between which thecross-shaft is positioned. The inboard sides of the left and rightclutch housings define pockets that cooperate to define a shaftreceptacle that receives the cross-shaft and each pocket includes firstand second ramp surfaces that are angled relative to one another so asto converge toward a neutral position located between the first andsecond ramp surfaces. The left and right clutch housings define springthrough-holes each having open inboard and outboard ends. Thedifferential includes left and right axle hubs positioned on oppositesides of the cross-shaft. The left and right axle hubs can be co-axiallyaligned along the axis of rotation. The differential has a left clutchpack that is housed at least partially within the left clutch housingand a right clutch pack that is housed at least partially within theright clutch housing. The left and right clutch packs each include firstclutch plates that are interleaved within respect to second clutchplates. The first clutch plates of the left clutch pack are carried withthe left clutch housing and the second clutch plates of the left clutchpack are carried with the left axle hub. Relative rotation about theaxis of rotation is prevented between the left clutch housing and theleft axle hub when a left clutch engagement pressure is applied to theleft clutch pack. Relative rotation about the axis of rotation ispermitted between the left clutch housing and the left axle hub whenonly a left clutch pre-load pressure is applied to the left clutch pack.The first clutch plates of the right clutch pack are carried with theright clutch housing and the second clutch plates of the right clutchpack are carried with the right axle hub. Relative rotation about theaxis of rotation is prevented between the right clutch housing and theright axle hub when a right clutch engagement pressure is applied to theright clutch pack. Relative rotation about the axis of rotation ispermitted between the right clutch housing and the right axle hub whenonly a right clutch pre-load pressure is applied to the right clutchpack. The differential further includes a plurality of clutch pre-loadsprings that cooperate to apply the left and right pre-load pressures tothe left and right clutch packs. The clutch pre-load springs can bepositioned inboard of the left and right clutch packs and each have aleft portion positioned within one of the spring through-holes of theleft clutch housing and a right portion positioned within one of thespring through-holes of the right clutch housing. Each of the clutchpre-load springs can be configured to apply a portion of the leftpre-load pressure to the left clutch pack and a portion of the rightpre-load pressure to the right clutch pack. Contact between thecross-shaft and one of the first and second ramp surfaces of the leftclutch housing causes the left clutch engagement pressure to be appliedto the left clutch pack. Contact between the cross-shaft and one of thefirst and second ramp surfaces of the right clutch housing causes theright clutch engagement pressure to be applied to the right clutch pack.The left engagement pressure is not applied to the left clutch pack whenthe cross-shaft aligns with the neutral position of the left clutchhousing. The right engagement pressure is not applied to the rightclutch pack when the cross-shaft aligns with the neutral position of theright clutch housing. The differential further includes outboard springsthat bias the left and right clutch actuators toward one another withoutapplying spring load through the left and right clutch packs.

A variety of additional aspects will be set forth in the descriptionthat follows. These aspects can relate to individual features and tocombinations of features. It is to be understood that both the foregoinggeneral description and the following detailed description are exemplaryand explanatory only and are not restrictive of the broad concepts uponwhich the examples disclosed herein are based.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a differential in accordance with the principles of thepresent disclosure, the differential is shown incorporated into anexample axle assembly of a vehicle drivetrain;

FIG. 2 is a partial exploded view of the differential of FIG. 1 showinga differential torque transfer arrangement exploded from a differentialcase of the differential;

FIG. 3 is a partial cross sectional view of the differential of FIG. 1;

FIG. 4 is a perspective view of the differential case of thedifferential of FIG. 1;

FIG. 5 is another perspective view of the differential case of FIG. 4;

FIG. 6 is an end view of the differential case of FIGS. 4 and 5;

FIG. 7 is an opposite end view of the differential case of FIGS. 4 and5;

FIG. 8 is a top view of the differential case of FIGS. 4 and 5;

FIG. 9 is a bottom view of the differential case of FIGS. 4 and 5;

FIG. 10 is a side view of the differential case of FIGS. 4 and 5;

FIG. 11 is an opposite side view of the differential case of FIGS. 4 and5;

FIG. 12 is a full cross sectional view of the differential of FIG. 1;

FIG. 13 is a fully exploded view of the differential torque transferarrangement of FIG. 12;

FIG. 14 is a perspective view of the differential torque transferarrangement of the differential of FIG. 13;

FIG. 15 is a top view of the differential torque transfer arrangement ofFIG. 13;

FIG. 16 is a side view of the differential torque transfer arrangementof FIG. 13;

FIG. 17 is a perspective view showing an outboard side of one of theclutch housings of the differential torque transfer arrangement of FIG.13;

FIG. 18 is a perspective view showing an inboard side of the clutchhousing of FIG. 17;

FIG. 19 is an outboard side view of the clutch housing of FIG. 17;

FIG. 20 is an inboard side view of the clutch housing of FIG. 17;

FIG. 21 is a top view of the clutch housing of FIG. 17;

FIG. 22 is a bottom view of the clutch housing of FIG. 17;

FIG. 23 is a side profile of the clutch housing of FIG. 17;

FIG. 24 is an opposite side profile of the clutch housing of FIG. 17;

FIG. 25 is a perspective view showing an inboard end of one of the axlehubs of the differential torque transfer arrangement of FIG. 17;

FIG. 26 is a perspective view showing an outboard end of the axle hub ofFIG. 25;

FIG. 27 is an exploded, perspective view of one of the clutch packs ofthe differential torque transfer arrangement of FIG. 13;

FIG. 28 is an end view of the differential torque transfer arrangementof FIG. 13 with an outboard thrust washer removed;

FIG. 28A is an enlarged view of a portion of FIG. 28;

FIG. 29 is a cross sectional view taken along section line 29-29 of FIG.16;

FIG. 30 is a cross sectional view taken along section line 30-30 of FIG.17;

FIG. 31 is a cross sectional view taken along section line 31-31 of FIG.17;

FIG. 32 shows a pre-load spring of the differential torque transferarrangement of FIG. 13, the pre-load spring is shown deformed inresponse to relative rotation between clutch housings of the torquetransfer arrangement;

FIG. 33 schematically shows the differential torque transfer arrangementof FIG. 13 oriented in a zero-ring speed condition;

FIG. 34 schematically shows the differential torque transfer arrangementof FIG. 13 in a forward ring drive condition with equal wheel speed;

FIG. 35 schematically shows the differential torque transfer arrangementof FIG. 13 in a forward ring drive condition with left wheel over-speed;

FIG. 36 schematically shows the differential torque transfer arrangementof FIG. 13 in a forward ring drive condition with right wheelover-speed;

FIG. 37 schematically shows the differential torque transfer arrangementof FIG. 13 in a reverse ring drive condition with equal wheel speed; and

FIG. 38 shows a main torque transfer assembly of the differential ofFIG. 1 in a compressed configuration suitable for allowing the maintorque transfer assembly to be loaded into the differential case ofFIGS. 4-11.

DETAILED DESCRIPTION

FIG. 1 illustrates an axle assembly 20 incorporating a differential 22in accordance with the principles of the present disclosure. The axleassembly 20 is part of a drive train 21 used to transfer torque from aprime mover 23 (e.g., an engine, a motor, or like power source) to leftand right wheels 24L, 24R. The differential 22 includes a differentialcase 26 and a differential torque transfer arrangement 28 positionedwithin the differential case 26. The differential case 26 carries a gear30 (e.g., a ring gear) that intermeshes with a drive gear 32 driven by adriveshaft 34 of the drivetrain 21. The differential torque transferarrangement 28 is configured to transfer torque from the differentialcase 26 to left and right axle shafts 36L, 36R that respectivelycorrespond to the left and right wheels 24L, 24R. The differential 22 isenclosed within an axle housing 38 that protects the differential 22 andcontains lubricant (e.g., oil) for lubricating moving parts within theaxle housing 38. The differential case 26 is mounted to rotate relativeto the axle housing 38 about an axis of rotation 40. In one example,bearings can be provided between the differential case 26 and the axlehousing 38 to allow the differential case 26 to freely rotate about theaxis of rotation 40 relative to the axle housing 38. The left and rightaxle shafts 36L, 36R are co-axially aligned along the axis of rotation40.

In certain examples, the axle assembly 20 can be incorporated into avehicle such as an all-terrain vehicle, a light utility vehicle, orother type of vehicle. The differential 22 of the axle assembly 20 isconfigured to prevent individual wheel spin and to provide enhancedtraction performance on a variety of surfaces such as mud, wet pavement,loose dirt and ice. In use, torque for rotating the differential case 26about the axis of rotation 40 is provided by the drive gear 32 thatintermeshes with gear 30 carried by the differential case 26. Thedifferential torque transfer arrangement 28 includes left and rightclutches (e.g., disc style clutches) configured to transfer torque fromthe rotating differential case 26 to the left and right axle shafts 36L,36R thereby driving rotation of the left and right wheels 24L, 24R. Whenthe vehicle is driven straight, the left and right clutches are bothactuated such that torque from the differential case 26 is transferredequally to the left and right axle shafts 36L, 36R. When the vehicleturns right, the left clutch is deactuated while the right clutchremains actuated. In this state, the differential torque transferarrangement 28 continues to drive rotation of the right axle shaft 36Rwhile the left axle shaft 36L is allowed to free wheel at a higher rateof rotation than the right axle shaft 36R. When the vehicle makes a leftturn, the right clutch is deactuated while the left clutch remainsactuated. In this state, the differential torque transfer arrangement 28continues to drive rotation of the left axle shaft 36L while the rightaxle shaft 36R is allowed to free wheel at a higher rotational speedthan the left axle shaft 36L.

It will be appreciated that the differential case 26 can also bereferred to as a differential carrier, a ring gear carrier, a carrier, adifferential casing, a differential housing or like terms. Also, theaxle housing 38 can be referred to as a carrier housing, a servicehousing or like terms.

Referring to FIG. 2, the differential torque transfer arrangement 28 isshown exploded from the differential case 26. The differential torquetransfer arrangement 28 includes a main assembly 50 and a cross-shaft52. To install the differential torque transfer arrangement 28 in thedifferential case 26, the main assembly 50 of the differential torquetransfer arrangement 28 is inserted laterally into the differential case26 through a main side opening 54. Once the main assembly 50 is insertedwithin the differential case 26, the cross-shaft 52 is used to retainthe main assembly 50 within the differential case 26. For example, thedifferential case 26 defines oppositely positioned shaft openings 56that align with a shaft receptacle 58 of the main assembly 50 when themain assembly 50 is loaded within the differential case 26. By insertingthe cross-shaft 52 through the shaft openings 56 and the shaftreceptacle 58, the main assembly 50 is secured within the differentialcase 26 as shown at FIG. 3. In the assembled configuration of FIG. 3,the cross-shaft 52 is positioned within the shaft receptacle 58 andextends through the main assembly 50. Opposite ends of the cross-shaft52 are positioned within the shaft openings 56 of the differential case26. A retaining pin 60 can be used to lock the cross-shaft 52 inposition relative to the differential case 26. The retaining pin 60 fitswithin a retaining pin opening 61 defined by the differential case 26.When the cross-shaft 52 is locked in place relative to the differentialcase 26 as shown at FIG. 3, the differential case 26 is configured tocarry the cross-shaft 52 such that the cross-shaft 52 and thedifferential case 26 rotate in unison with one another as thedifferential case 26 is rotated about the axis of rotation 40 by thedrive gear 32. The configuration allows torque from the drive gear 32 tobe transferred through the differential case 26 to the cross-shaft 52.

The differential case 26 includes a main case body 70 having an integralconstruction. The term “integral construction” means that the main casebody 70 is not intended to be taken apart. For example, the main casebody 70 can have a unitary, one piece construction. Alternatively, themain case body 70 can include multiple pieces that are connectedtogether by a fastenerless-type connection (e.g., a weld) that isintended to be permanent. In certain examples, the main case body 70 hasa construction that cannot be taken apart with destroying the main casebody 70.

Referring to FIGS. 4-11, the main case body 70 includes a left end 70Land right end 70R. The left end 70L of the main case body 70 defines aleft axle shaft opening 72L and the right end 70R of the main case body70 defines a right axle shaft opening 72R. The left and right axle shaftopenings 72L, 72R are coaxially aligned along the axis of the rotation40 of the differential case 26. As best shown at FIGS. 10 and 11, themain case body 70 defines the main side openings 54 and the shaftopenings 56 of the differential case 26. The main side openings 54provide access to an interior 74 of the main case body 70 and arepositioned at diametrically opposite sides of the main case body 70. Theshaft openings 56 are configured to receive end portions of thecross-shaft 52 and are positioned at diametrically opposite sides of themain case body 70. In the depicted example, the main side openings 54are defined at front and back sides of the main case body 70 and theshaft openings are defined at top and bottom sides of the main case body70.

Referring back to FIG. 3, the interior 74 of the main case body 70includes a main chamber 76 and left and right pockets 78L, 78R. The leftand right pockets 78L, 78R are depicted as being coaxially aligned withthe axis of rotation 40 of the differential case 26. The main case body70 further includes a gear mounting flange 80 that extendscircumferentially around an exterior of the main case body 70. The gearmounting flange 80 is depicted as being coaxially aligned with the axisof rotation 40 of the differential case 26. In one example, the gearmounted flange 80 is configured for facilitating mounting the gear 30 tothe main case body 70. For example, the gear mounted flange 80 candefine fastener openings 82 for receiving fasteners used to attach thegear 30 to the main case body 70. Once the gear 30 has been attached tothe main case body 70, the gear 30 and the differential case 26 areconfigured to rotate in unison with one another about the axis ofrotation 40 when the gear 30 is driven by the drive gear 32.

Referring now to FIGS. 12 and 13, the differential torque transferarrangement 28 defines a central reference plane 84 that longitudinallybisects the cross-shaft 52 of the differential torque transferarrangement 28. The differential torque transfer arrangement 28 includesleft and right assemblies 86L, 86R positioned generally on oppositesides of the central reference plane 84. The left assembly 86L includesa left axle hub 88L, a left clutch actuator 90L, a left inboard thrustwasher 92L, a left clutch pack 94L, a left outboard thrust washer 96Land left outboard springs 98L. The right assembly 86R includes a rightaxle hub 88R, a right clutch actuator 90R, a right inboard thrust washer92R a right clutch pack 94R, a right outboard thrust washer 96R andright outboard springs 98R. The differential torque transfer arrangement28 also includes clutch pre-load springs 100 that traverse (i.e., extendacross, intersect, etc.) the central reference plane 84 (see FIG. 31).The central reference plane 84 extends along an interface between theleft and right clutch actuators 90L, 90R and is perpendicular withrespect to the axis of rotation 40.

The clutch pre-load springs 100 form a first spring arrangement thatapplies pre-loads to the left and right clutch packs 94L, 94R. In oneexample, each of the clutch pre-load springs 100 applies pre-loadpressure to both the left and right clutch packs 94L, 94R withoutapplying pressure to the left and right clutch actuators 90L, 90R. Thus,the clutch pre-load springs 100 do not bias the left and right clutchactuators 90L, 90R apart from one another. The clutch pre-load springs100 are positioned inboard of the left and right clutch packs 94L, 94R.The left and right outboard springs 98L, 98R form second springarrangements configured to bias the left and right clutch actuators 90L,90R toward one another (see FIG. 30). In one example, the second springarrangement is configured to not transfer spring pressure through theleft and right clutch packs 94L, 94R.

In certain examples of the present disclosure, the left and right clutchactuators 90L, 90R can be referred to as left and right clutch housings.In such examples, the left and right clutch actuators 90L, 90R caninclude structure for at least partially housing left and right clutchpacks 94L, 94R. In the depicted example, the components of the left andright assemblies 86L, 86R can have identical constructions. Thus, theleft and right axle hubs 88L, 88R can be referred to generally as axlehubs 88; the left and right clutch actuators 90L, 90R can be referred togenerally as a clutch actuators 90; the left and right inboard thrustwashers 92L, 92R can be referred to generally as inboard thrust washers92; the left and right clutch packs 94L, 94R can be referred togenerally as clutch packs 94; the left and right outboard thrust washers96L,96R can be referred to generally as outboard thrust washers 96; andthe left and right outboard springs 98L, 98R can be referred togenerally as outboard springs 98.

Referring again to FIG. 12, the differential torque transfer arrangement28 is shown mounted within the differential case 26. With thedifferential torque transfer arrangement 28 mounted within thedifferential case 26 as shown at FIG. 12, the axle hubs 88, the clutchactuators 90, the inboard thrust washers 92, the clutch packs 94, andthe outboard thrust washers 96 are all generally coaxially aligned withthe axis of rotation 40 of the differential case 26. Outboard endportions of the left and right axle hubs 88L, 88R fit within the leftand right pockets 78L, 78R of the main case body 70 of the differentialcase 26. The left and right outboard thrust washers 96L, 96Rrespectively abut against left and right stops 79L, 79R defined by themain case body 70. The left and right stops 79L, 79R oppose the pre-loadpressure applied to the left and right clutch packs 94L, 94R by theclutch pre-load springs 100. For example, the clutch pre-load springs100 apply outward axial spring load through the inboard thrust washers92 to the clutch packs 94. In this way, the clutch packs 94 are axiallycompressed between the inboard thrust washers 92, (which are outwardlybiased by the clutch pre-load springs 100) and the outboard thrustwashers 96 (which are held in place by the stops 79 of the main casebody 70).

FIGS. 14-16 show the differential torque transfer arrangement 28 in anassembled configuration and FIGS. 17-24 show one of the clutch actuators90 in isolation from the remainder of the differential torque transferarrangement 28. When the differential torque transfer arrangement 28 isin the assembled configuration as shown at FIGS. 14-16, inboard sides102 of the left and right clutch actuators 90L, 90R cooperate to definethe shaft receptacle 58 in which the cross-shaft 52 is received. Forexample, as shown at FIGS. 18 and 20, the inboard side 102 of eachclutch actuator 90 includes first and second actuator pockets 104, 106.The actuator pockets 104, 106 are positioned between inner and outercircumferential boundaries B1, B2 of each clutch actuator 90. The innercircumferential boundary B1 corresponds to an inner diameter D1 of eachclutch actuator 90 and the outer circumferential boundary B2 correspondsto an outer diameter D2 of each clutch actuator 90. The innercircumferential boundary B1 defines a central opening 108 of each clutchactuator 90. The inner and outer circumferential boundaries B1, B2 arecylindrical and are centered about a central axis 110 of each clutchactuator 90. When the left and right clutch actuators 90L, 90R aremounted within the differential case 26, the central axes 110 coaxiallyalign with the axis of rotation 40 of the differential case 26.

As best shown at FIGS. 18 and 20, each of the actuator pockets 104, 106includes a neutral position 112 that corresponds to a deepest portion ofeach of the actuator pockets 104, 106. The neutral positions 112 arepositioned on diametrically opposite sides of the central axes 110 ofthe clutch actuators 90 (i.e., the neutral positions are aligned along adiameter line of each clutch actuator 90). The actuator pockets 104, 106are each defined in part by first and second ramp surfaces 114, 116. Thefirst and second ramp surfaces 114, 116 are angled to converge towardthe neutral positions 112. The first ramp surfaces 114 angle away fromthe neutral positions 112 as the first ramp surfaces 114 extend in afirst rotational direction 118 (FIG. 20) about the central axis 110. Thesecond ramp surfaces angle away from the neutral positions 112 as thesecond ramp surfaces 116 extend in a second rotational direction 120(FIG. 20) about the central axis 110. The actuator pockets 104, 106 alsoinclude shaft insertion chamfers 122 positioned at the neutral positions112 of the actuator pockets 104, 106 adjacent the outer circumferentialboundary B2 of each clutch actuator 90. When the differential torquetransfer arrangement 28 is assembled, the first and second actuatorpockets 104, 106 of the left clutch actuator 90L cooperate with thefirst and second actuator pockets 104, 106 of the right clutch actuator90R to define the shaft receptacle 58. The shaft insertion chamfers 122provide an angle transition at the outer circumferential boundaries B2of the left and right clutch actuators 90L, 90R for providing a graduallead-in to the first and second actuator pockets 104, 106. The graduallead-in is configured to facilitate inserting the cross-shaft 52 intothe shaft receptacle 58 to secure the main assembly 50 of thedifferential torque transfer arrangement 28 within the differential case26 during assembly of the differential 22. The shaft insertion chamfers122 assist in facilitating forcing the left and right clutch actuators90L, 90R apart against the bias of the outboard springs 98 as thecross-shaft 52 is inserted into the shaft receptacle 58.

The left and right clutch actuators 90L, 90R also include an interlockstructure for limiting relative rotation between the left and rightclutch actuators 90L, 90R about the axis of rotation 40 of thedifferential 22. For example, referring to FIGS. 18 and 20, the inboardsides 102 of the clutch actuator 90 include relative rotation limitersin the form of posts 124 and post receptacles 126. As shown in FIG. 20,the post 124 and the post receptacle 126 of each clutch actuator 90 arepositioned on diametrically opposite sides of the central opening 108and are aligned along a diameter line of each clutch actuator 90. Eachpost receptacle 126 is defined in part by opposing first and secondstops surfaces 128, 130. A spacing S between the stops surfaces 128, 130is larger than a cross dimension CD of each post 124. When the torquetransfer arrangement 28 is assembled, the post 124 of the left clutchactuator 90L fits within the post receptacle 126 of the right clutchactuator 90R and the post 124 of the right actuator 90R fits within thepost receptacle 126 of left clutch actuator 90L (see FIGS. 16 and 29).

Contact between the posts 124 and the stop surfaces 128, 130 allows foronly a limited range of relative rotational movement between the leftand right clutch actuators 90L, 90R about the axis of rotation 40. Eachof the posts 124 has a contact surface of 132 that engages the stopsurfaces 128, 130 to limit relative rotation between the left and rightclutch actuators 90L, 90R. For example, the contact surfaces 132 engagethe first stop surfaces 128 to limit the amount that: a) the left clutchactuator 90L can rotate in the first direction 118 relative to the rightclutch actuator 90R; and b) the right clutch actuator 90R can rotate inthe second direction 120 relative to the left clutch actuator 90L.Similarly, the contact surfaces 132 engage the second stop surfaces 130to limit the amount that: a) the left clutch actuator 90L can rotate inthe second direction 120 relative to the right clutch actuator 90R; andb) the right clutch actuator 90R can rotate in the first direction 118relative to the left clutch actuator 90L. In one example, the stopsurfaces 128, 130 have a different shape or profile than the contactsurfaces 132. In one example, the contact surfaces 132 are curved andthe stop surfaces 128, 130 are planar. In the depicted example, thecontact surface 132 of each of the posts 124 is cylindrical and extendsaround a periphery of each of the posts 124. In certain examples, thecontact surfaces 132 are configured to make line contact with the stopsurfaces 128, 130.

During normal straight, forward driving conditions, the cross-shaft 52engages the ramp surfaces 114 (see FIG. 34) causing actuation of theclutch packs 94 such that torque is transferred from the cross-shaft 52through the actuators 90, the clutch packs 94 and the side hubs 88 tothe axle shafts 36. In this condition, the posts 124 are centered withinthe post receptacles 126 (see FIG. 34). Since the spacings S between thestop surfaces 128, 130 of the post receptacles 126 are larger than thecross-dimension CD of the posts 124, gaps G are defined between theposts 124 and the stop surfaces 128, 130 when the posts 124 are centeredwithin the post receptacles 126. The gaps G are sized to correspond witha distance D. The distance D represents the distance of relativemovement between the cross-shaft 52 and one of the actuators 90 as theactuator 90 moves/rotates relative to the cross-shaft 52 from a fullyengaged position (e.g., see actuator 90L at FIG. 34) to a non-engagedposition (e.g., see actuator 90L at FIG. 35). In the fully engagedposition, engagement exists between the cross-shaft 52 and the rampsurfaces 114 of the actuator 90 such that the clutch pack 94corresponding to the actuator 90 is axially compressed and fullyactuated. In the non-engaged position, the ramp surfaces 114 of theactuator 90 are disengaged from the cross-shaft 52 such that onlypre-load pressure is applied to the corresponding clutch pack 94. Thecenterline of the cross-shaft 52 aligns with the neutral position 112 ofthe actuator 90 when the actuator 90 is in the non-engaged position.

During an overspeed condition, the actuator 90 corresponding to theoverspeeding wheel rotates relative to the cross-shaft 52 and the otheractuator 90 from the engaging position toward the non-engaging position.One of the gaps G of each relative rotation limiter (e.g., of each post124 and post receptacle 126) closes as the actuator 90 moves toward thenon-engaging position. Contact between the posts 124 and correspondingones of the stop surfaces 128, 130 positively stops the actuator 90 atthe non-engagement position. For example, FIG. 35 shows a conditionwhere one of the posts 124 engages the stop surface 128 to positivelystop the actuator 90L in the non-engaging position. Similarly, FIG. 36shows a condition where one of the posts 124 engages the stop surface130 to positively stop the actuator 90R in the non-engaging position.

The distance D is dependent upon the angle of the ramp surfaces 114 andthe axial displacement needed to fully compress the clutch pack 94; andthe amount of relative rotation required to achieve D is dependent uponthe distance the contact locations between the cross-shaft and the rampsurfaces are radially spaced from the axis of rotation 40 of thedifferential. It is beneficial for the gaps G to precisely correspond tothe distance D to ensure precise alignment of the cross-shaft 52 withthe neutral position 112 when the actuator 90 is in the non-engagedposition. In determining the value of G required to achieve a desiredvalue of D, the radial spacing from the axis 40 of the lines of contactof the interlock structures as well as the radial spacing from the axis40 of the contact locations between the ramps and the cross-shaft aretaken into consideration. The degree of relative rotation allowedbetween the left and right clutch actuators 90L, 90R preciselycorresponds to the rotational distance between the fully engagedposition and the non-engaged position. This precision is enabled atleast in part by the precise nature of the line contact configurationused by the relative rotation limiters (i.e., the post 124 and stopsurfaces 128, 130). Such precision ensures that during an overspeedcondition, the neutral position 112 of the actuator 90 corresponding tothe overspeeding wheel does not rotate past the center of thecross-shaft 52 and inadvertently engage the trailing ramp surfacethereby causing the clutch 94 to be re-actuated and the wheel to beunintentionally locked-up. In this way, the durability and lifespan ofthe differential 22 is enhanced by inhibiting heat and wear associatedwith unintentional wheel lock-ups and minimization of parasiticdriveline losses.

The left and right clutch actuators 90L, 90R also include structure forreceiving the clutch pre-load springs 100. For example, as shown inFIGS. 17-20, each of the clutch actuators 90 includes a plurality ofthrough-holes 134 that extend through each clutch actuator 90 from theinboard side 102 to an outboard side 136. The through-holes 134 candefine through-hole axes 138 that are parallel with respect to thecentral axis 110. The through-holes 134 are shown circumferentiallyspaced about the central axis 110. In the depicted example, four of thethrough-holes 134 are defined by each of the clutch actuators 90. Thethrough-holes 134 are located between the inner and outercircumferential boundaries B1, B2 of each clutch actuator 90. In theexample of FIG. 20, a first of the through-holes 134 is locatedcircumferentially between the first actuator pocket 104 and the postreceptacle 126; a second of the through-holes 134 is locatedcircumferentially between the post receptacle 126 and the secondactuator pocket 106; a third of the through-holes 134 is locatedcircumferentially between the second actuator pocket 106 and the stoppost 124; and a fourth of the through-holes 134 is locatedcircumferentially between the stop post 124 and the first actuatorpocket 104.

FIG. 31 is a cross-sectional view showing the assembled torque transferarrangement 28. As shown at FIG. 31, the pre-load springs 100 aremounted within the through-holes 134 of the left and right clutchactuators 90L, 90R. For example, each of the pre-load springs 100includes a first portion 140 that extends through one of thethrough-holes 134 of the left clutch actuator 90L and an second portion142 that extends through one of the through-holes 134 of the rightclutch actuator 90R. The pre-load springs 100 traverse the centralreference plane 84 and are compressed between the left and right inboardthrust washers 92L, 92R. In this way, each of the pre-load springs 100applies a pre-load force to both the left and right clutch packs 94L,94R without applying pre-load pressure to the left and right clutchactuators 90L, 90R. In the depicted example, each of the through-holes134 has open inboard and outboard ends 144, 146 and the pre-load springs100 extend completely through the through-holes 134. A benefit of thepass-through mounting configuration of the pre-load springs 100 is thatthe pre-loads are equally balanced on both the left and right clutchpacks 94L, 94R. This is true even if variations exist in the internalside-to-side comparative measurement between the centerline of thecross-shaft 52 and internal thrust surfaces of the differential casing26 and or relative axial sizing variations in the left and right clutchactuators 90L, 90R and/or sizing variations in the clutch packs 94L, 94Rthemselves. In other words, the pass-through configuration of thepre-load springs is adapted to take-up or otherwise compensate fortolerance mismatches within the differential such that equal pre-loadsare applied to both the left and right clutch packs 94L, 94R. Thepass-through mounting configuration of the pre-load springs also assistin maintaining uniform pre-loads even in the case of non-uniform clutchwear.

Since the pre-load springs 100 extend across the central reference plane84, it will be appreciated that the pre-load springs 100 flex when theleft and right clutch actuators 90L, 90R rotate relative to one anotherwithin the range of relative rotational movement allowed by the rotationlimiting arrangement (i.e., the stop posts 124 and the post receptacles126). For example, FIG. 32 shows one of the pre-load springs 100 flexedto accommodate relative rotational movement between the left and rightclutch actuators 90L, 90R. This provides torsional rotational dampeningbetween the left and right clutch actuators 90L, 90R. To better allowthe pre-load springs 100 to accommodate the limited amount of rotationalmovement allowed between the left and right clutch actuators 90L, 90R,the through-holes 134 can have a tapered configuration. For example, thethrough-holes 134 can have truncated conical configuration definingmajor diameters and minor diameters. In other examples, other taperconfigurations can be used where the cross-dimensions of thethrough-holes vary along the lengths of the through holes. In oneexample, the through holes can have a greater rate of taper in acircumferential orientation as compared to a radial orientation.

As shown at FIG. 31, the through-holes 134 are configured to havetapered portions 145 that provide the through-holes 134 with largerdiameters (i.e., major diameters) adjacent the inboard ends 144 ascompared to the outboard ends 146. In certain embodiments, the majordiameters of the through-holes 134 are located at the inboard sides ofthe clutch actuators 90. In certain examples, the at least portions ofthe through-holes 134 can gradually enlarge in diameter as thethrough-holes 134 extend in inboard directions along the taperedportions 145. In certain examples, the through-holes 134 can havecylindrical, non-tapered portions 147 adjacent the outboard ends 146 ofthe through-holes 134. The non-tapered portions 147 are located at theroots of the tapered portions 145 and form cylindrical portions thatclosely fit about end portions of the pre-load springs 100. Thenon-tapered portions 147 provide a piloting function to fix the positionof the ends of the springs 100 relative to the actuators 90 to assist inproviding torsional control for dynamic dampening. In one example, thenon-tapered portions 147 extend axially for at least one coil length toprovide suitable piloting and stabilizing of the ends of the springs100. The combination of the tapered portions 145 and non-taperedportions 147 assists in optimizing the rotational dampening provided bythe pre-load springs 100 between the left and right clutch actuators90L, 90R.

Referring to FIGS. 17 and 19, the outboard side 136 of each of theclutch actuators 90 includes structure for accommodating the outboardsprings 98. For example, the clutch actuators 90 have outboard springholes 148 for receiving the outboard springs 98. As shown in FIG. 30,the outboard spring holes 148 have open ends 150 at the outboard side136 of each clutch actuator 90 and closed ends 152 positioned oppositethe open ends 150. The outboard spring holes 148 define spring hole axes154 that are parallel to the central axis 110. The outboard spring holes148 are circumferentially spaced about the central axis 110 and arepositioned near the outer circumferential boundary B2 of each clutchactuator 90.

Referring still to FIGS. 17 and 19, the open ends 150 of the outboardspring holes 148 are positioned within tab pockets 156 defined by theoutboard side 136 of each of the clutch actuators 90. The tab pockets156 are shown having a truncated, triangular shape. In the depictedexample, the tab pockets 156 are configured to receive tabs 158 (seeFIGS. 13-16) of the outboard thrust washers 96. The tabs 158 can havetruncated, triangular shapes that complement the truncated, triangularshapes of the tab pockets 156. The tabs 158 function to retain theoutboard springs 98 within the outboard spring holes 148 (see FIGS.14-16 and 30). When the torque transfer arrangement 28 is assembled, thetabs 158 fit within the tab pockets 156 to provide a keying functionthat prevents relative rotation between the clutch actuators 90 and theoutboard thrust washers 96. The tabs 158 also function to retain theoutboard springs 98 within the corresponding outboard spring holes 148.In this regard, the tabs 158 also define locator holes 216 (see FIG. 13)that receive the outboard ends of the outboard springs 98. The locatorholes 216 maintain the springs 98 along their functional axes regardlessof rotational speed and inertia. The locator holes 216 also prevent thesprings 98 from slipping out of position and possibly damaging thedifferential.

FIG. 30 is a cross-sectional view showing the differential 22. As shownat FIG. 30, when the differential torque transfer arrangement 28 isassembled within the differential case 26, the outboard springs 98 arecompressed between the outboard thrust washers 96 and the clutchactuators 90. Thus, the outboard springs 98 function to bias the leftand right clutch actuators 90L, 90R together against the cross-shaft 52.The compressive spring load provided by the outboard springs 98 assistsin limiting rattle or vibrations between the cross-shaft 52 and the leftand right clutch actuators 90L, 90R. In one example, the outboardsprings 98 are laterally offset from the clutch packs 94 and do notapply a compressive load through the clutch packs 94. Instead, only theclutch pre-load springs 100 apply pre-load to the clutch packs 94. Sincethe pre-load springs 100 extend through the through-holes 134 andtherefore do not apply pre-load pressure to the clutch actuators 90, thepre-load force provided by the pre-load springs 100 does not oppose thecompressive load provided by the outboard springs 98. Thus, the springloads applied by the outboard springs 98 and the pre-load springs 100are isolated from one another such that the clutch-pre load applied tothe clutches 94 and the compressive load applied to the clutch actuators90 can be independently established.

In one example, the clutch pre-load applied to each clutch pack allowsthe clutch packs to transfer a pre-load torque value that is less than arepresentative wheel slip torque value corresponding to the outsidewheel during a turn. The representative wheel slip torque value (i.e.,the torque required to have the wheel slip relative to the ground) isdependent upon the gross weight of the vehicle and a selectedcoefficient of friction between the ground and the wheel thatcorresponds to a low traction condition.

Referring to FIGS. 17 and 19, the outboard sides 136 of the clutchactuators 90 form clutch housings 160 for receiving and housing theclutch packs 94. For example, the outboard sides 136 of the clutchactuators 90 define receptacles for receiving the clutch packs 94. Asshown at FIG. 27, each of the clutch packs 94 includes first and secondclutch plates 162, 164 (e.g., friction disks) that are interleavedrelative to one another. The first clutch plates 162 interface with theclutch actuators 90 at first mechanical interfaces 166 (see FIGS. 28 and28A) and the second clutch plates 164 interface with the axle hubs 88 atsecond mechanical interfaces 168 (see FIGS. 28 and 28A). In one example,first mechanical interface 166 is configured to prevent relativerotation between the first clutch plates 162 and the actuators 90 andthe second mechanical interface 168 is configured to prevent relativerotation between the second clutch plates 164 and the axle hubs 88. Inone example, first and second mechanical interfaces 166, 168 includesplined interfaces. It will be appreciated that other types ofmechanical interfaces for preventing relative rotation can also be used.

In the depicted example of FIGS. 28 and 28A, the first mechanicalinterface 166 is a splined interface. For example, the first clutchplates 162 include splines 170 that fit within spline receptacles 172defined by the clutch actuators 90. Also, the clutch actuators 90 definesplines 174 that fit within spline receptacles 176 defined by the firstclutch plates 162. In the depicted example, the spline receptacles 176have transverse cross-sectional areas A1 (see FIG. 28) and the splines174 have transverse cross-sectional areas A2 (see FIGS. 19 and 28). Inone example, the transverse cross-sectional areas A2 of the splines 174each occupy no more than 85% of the corresponding transversecross-sectional areas A1 of the spline receptacles 176 in which they arereceived.

The unoccupied space within the spline receptacles 176 forms axial oilflow paths 178 within the spline receptacles 176 for allowing lubricant(e.g., oil) to escape from between the first and second clutch plates162, 164 when the clutch packs 94 are actuated. By providing an escapepath for the lubricant, the responsiveness of the clutch packs 94 toactuation are enhanced. In the depicted example, the splines 174 havetruncated triangular profiles having truncated ends and the splinereceptacles 176 include unoccupied portions located adjacent to thetruncated ends of the splines 174. The unoccupied portions of the splinereceptacles 176 define the axial lubricant flow paths 178. In thedepicted example, the spline receptacles 176 have truncated triangularprofiles having receptacle heights that are larger than correspondingspline heights of the truncated triangular profiles of splines 174. Inthe depicted, the axial flow paths 178 are provided at the firstmechanical interface 166. In other examples, similar axial flow pathscan be provided at the second mechanical interface 168. Additionally, itwill be appreciated that spline shapes other than those specificallydepicted can also be used.

Referring to FIG. 19, the clutch actuators 90 includes circumferentialwalls 180 that surround the clutch packs 94 and also surround the axesof rotation 110. The circumferential walls 180 form at least portions ofthe clutch housings 160. The circumferential walls 180 define openings182 (see FIGS. 16-18) that provide radial flow paths that allowlubricant (e.g., oil) to escape from between the first and second clutchplates 162, 164 when the clutch packs 94 are compressed together duringactuation. The side positioning of the openings 182 allows centrifugalforce to assist in exhausting lubricant from the clutch packs 94 throughthe clutch housings 160. The through-holes 134 receiving the pre-loadsprings 100 also assist in enlarging the venting area provided forallowing lubricant to escape from between the first and second clutchplates 162, 164 when the clutch packs 94 are compressed together duringactuations. In this regard, the through-holes 134 are in fluidcommunication with annular grooves 200 defined at the interface betweenthe clutch actuators 90 and the inboard sides of the inboard thrustwashers 92. In the depicted example, the annular grooves 210 are definedwithin the inboard sides of the inboard thrust washers 92. The inboardthrust washers 90 also define circumferentially spaced-apart axialthrough-holes 212 that intersect the annular grooves 210. Duringactuation of the clutch packs 94, oil/lubricant is pressed from betweenthe clutch plates 160, 162 of the clutch packs 94, travels through thespline receptacles 176 and exits the inboard sides of the clutch packs94 through the axial through-holes 212. From the axial through-holes202, the oil/lubricant flows through the annular grooves 210 to thethrough-holes 134 which provide a path for allowing the oil/lubricant toaxially exit the clutch housings 164 of the clutch actuators 90.Circumferentially spaced-apart axial through-holes 214 can also bedefined though the outboard thrust washers 96 for venting oil/lubricantout the outboard ends of the clutch packs 94 during axial compression ofthe clutch packs 94. The effective venting/exhausting of lubricant fromthe clutch packs 94 assists in improving the responsiveness andactuation time of the clutch packs 94.

Referring to FIGS. 25 and 26, the axle hubs 88 are generally cylindricalin shape and include outer splines 184 that mate with correspondinginner splines 186 (see FIG. 27) of the second clutch plates 164 to formthe second mechanical interface 168 (see FIG. 28). As indicated above,the second mechanical interface 168 is configured to prevent relativerotation between the axle hubs 88 and the second clutch plates 164 suchthat the second clutch plates 164 rotate in unison with the axle hubs88. Similarly, first mechanical interfaces 166 prevent relative rotationbetween clutch actuators 90 and the first clutch plates 162 such thatthe first clutch plates 162 rotate in unison with the clutch actuators90. The axle hubs 80 are also configured to rotate in unison with theaxle shafts 36. For example, the axle shafts 36 can be connected to theaxle hubs 88 by mechanical interfaces that prevent relative rotationbetween the axle hubs 88 and the axle shafts 36. As shown at FIGS. 25and 26, the axle hubs 88 include inner splines 188 that mate withcorresponding outer splines of the axle shafts 36 such that relativerotation is provided between the axle hubs 88 and the axle shafts 36.When the differential 22 is assembled as shown at FIG. 31, the axle hubs88 extend through the clutch packs 94 and inboard ends of the axle hubs88 fit within the central openings 108 of the clutch actuators 90.

In use of the differential 22, torque from the drive gear 32 can be usedto rotate the differential case 26 in either a forward rotationaldirection or a reverse rotational direction about the axis of rotation40. When the differential case 26 is rotated in a forward rotationaldirection under normal straight driving conditions, the vehicle ispropelled in a forward direction. In contrast, when the differentialcase 26 is rotated in the reverse rotational direction under normalstraight driving conditions, the vehicle is propelled in a reversedirection.

When the differential case 26 is rotated in the forward direction undernormal straight driving conditions, contact between the cross-shaft 52and the ramp surfaces 114 of the actuators 90 causes the actuators 90 tobe forced in outboard axial directions thereby causing the clutch packs94 to be actuated. When the clutch packs 94 are actuated, the clutchplates 162, 164 are axially compressed together thereby preventing theclutch plates 162, 164 from rotating relative to one another. When thisoccurs, forward driving torque is transferred from the cross-shaft 52through the actuators 90 and the clutch packs 94 to the correspondingaxle hubs 88. The axle hubs 88 then transfer the forward driving torqueto their corresponding axle shafts 36 which transfer the forward torqueto their corresponding wheels 24 thereby causing rotation of the wheels24 in the forward direction.

When the differential case 26 is rotated in the reverse direction undernormal straight driving conditions, contact between the cross-shaft 52and the ramp surfaces 116 of the actuators 90 causes the actuators 90 tobe forced in outboard axial directions thereby causing the clutch packs94 to be actuated. When the clutch packs 94 are actuated, thecorresponding clutch plates 162, 164 are axially compressed togetherthereby preventing the clutch plates 162, 164 from rotating relative toone another. When this occurs, reverse driving torque is transferredfrom the cross-shaft 52 through the actuators 90 and the clutch packs 94to the corresponding axle hubs 88. The axle hubs 88 then transfer thereverse driving torque to their corresponding axle shafts 36 whichtransfer the reverse torque to their corresponding wheels 24 therebycausing rotation of the wheels 24 in the reverse direction.

When the cross-shaft 52 is aligned with the neutral position 112 of oneof the actuation pockets 104, 106, the corresponding clutch pack 94 isnot axially compressed by the corresponding actuator 90 and is thereforein a non-actuated state. When the clutch pack 94 is in a non-actuatedstate, the first clutch plates 162 and the second plates 164 are onlysubject to pre-load pressure and can rotate relative to one anotherduring a wheel overspeed condition thereby permitting the correspondingaxle hub 88 and its corresponding axle shaft 36 to rotate relative tothe corresponding actuator 90 during the wheel overspeed condition.

The pre-load provided on the left and right clutch packs 94L, 94R by thepre-load springs 100 insures that proper actuation takes place when thecross-shaft 52 engages the ramp surfaces 116, 118. The pre-load providedby the springs 100 should be large enough such that the clutch packsprovide sufficient resistance to rotational movement of the actuators 90about the axis 40 for the cross-shaft 52 to ride up on the ramps 116,118 and cause actuation of the clutch packs as differential case 26 andthe cross-shaft 52 carried therewith are rotated about the axis 40during normal driving conditions. Absent the friction between the clutchplates 162, 164 generated by the pre-load, insufficient axial actuationforce can be generated by the contact between the cross-shaft 52 and theramp surfaces 116, 118. In this situation, the cross-shaft 52 wouldmerely rotate the left and right clutch actuators 90L, 90R about theaxis of rotation 40 without generating enough force to axially compressand actuate the left and right clutch packs 94L, 94R. Thus, a free-spincondition would exist where torque would not be applied through theclutch packs 94L, 94R to the left and right axle hubs 88L, 88R and theircorresponding axle shafts 36L, 36R. When only pre-load pressure isapplied to the clutch packs 94, insufficient friction is providedbetween the clutch plates 162, 164 to prevent the clutch plates fromrotating relative to one another during a free-wheel (i.e., wheeloverspeed) condition as would occur during a vehicle turn.

FIGS. 33-37 schematically illustrate various operational states of thedifferential 22. For example, FIG. 33 shows the differential 22 in a“zero ring speed” state in which no torque is being applied to thedifferential case 26 by the drive gear 32 and the differential case 26is not rotating about the axis of rotation 40. In the “zero ring speed”state, the stop posts 124 are centered between the stop surfaces 128,130 of the post receptacles 126 and the cross-shaft 52 is aligned withthe neutral positions 112 of the actuation pockets 104, 106.

FIG. 34 shows the differential 22 in a state in which the differentialcase 26 is being rotated in the forward rotational direction about theaxle of rotation 40 by the drive shaft 34 and the vehicle is beingdriven straight. In this condition, the cross-shaft 52 engages the firstramp surfaces 114 of the left and right clutch actuators 90L, 90Rthereby by forcing the left and right clutch actuators 90L, 90Routwardly (see arrows 300) to actuate the left and right clutch packs94L, 94R by axially compressing the left and right clutch packs 94L,94R. With the left and right clutch packs 94L, 94R actuated, relativerotation is prevented between the first and second clutch plates 162,164 of the clutch packs 94L, 94R. Thus, torque from the differentialcase 26 and the cross-shaft 52 is transferred from the left and rightclutch actuators 90L, 90R through the left and right clutch packs 94L,94R to the left and right axle hubs 88L, 88R and the left and right axleshafts 36L, 36R to cause the left and right wheels 24L, 24R to berotated in the forward direction. In the forward drive condition of FIG.34, the stop posts 124 are centered between the stop surfaces 128, 130of the post receptacles 126. Thus, FIG. 34 shows forward rotationaldrive with equal wheel speed.

FIG. 35 shows a condition where the differential case 26 is beingrotated in the forward direction about the axis of rotation 40 and theleft wheel 24L is being rotated in the forward direction faster than theright wheel 24R. This type of condition occurs when the vehicle ismaking a right turn. When a right turn is being made, the increasedspeed of the left wheel 24L causes the left clutch actuator 90L torotate forward relative to the right clutch actuator 90R. As the leftclutch actuator 90L rotates forward relative to the right clutchactuator 90R, the first ramp surface 114 of the left clutch actuator 90Ldisengages from the cross-shaft 52 such that the left clutch pack 94L isno longer actuated. While the left clutch pack 94L is in a non-actuatedstate, the first and second clutch plates 162, 164 of the left clutchpack 94L can rotate relative to one another thereby allowing the leftaxle hub 88L and the left axle shaft 36L to rotate faster in a forwarddirection than the left clutch actuator 90L. In this way, thede-actuation of the left clutch actuator 90L permits the left wheel 24Lto rotate at a faster speed in the forward direction as compared to theright wheel 24R. When the differential 22 is operating in the leftover-speed condition of FIG. 35, the stop posts 124 contact the stopsurfaces 128 to limit the amount of relative rotation that is permittedbetween the left and right clutch actuators 90L, 90R. This prevents theneutral position 112 of the left actuator 90L from rotating past thecross-shaft 52. In this way, the second ramp surfaces 116 of the leftclutch actuator 90L are prevented from contacting the shaft 52.Unintended engagement between the cross-shaft 52 and the second rampsurface 116 during an overspeed condition would cause the left clutchpack 94L to be actuated which would lock-up the left wheel.

FIG. 36 shows the differential 22 in a condition in which thedifferential case 26 is being driven in a forward rotational directionabout the axis of rotation 40 and the right wheel 24R is rotating at ahigher speed than the left wheel 24L. This condition would occur whenthe vehicle is making a left turn. When a left turn takes place, theright clutch actuator 90R rotates forwardly relative to the left clutchactuator 90L causing the first ramp surfaces 114 of the right clutchactuator to disengage from the cross-shaft 52 such that the right clutchpack 94R is de-actuated. With the right clutch pack 94R de-actuated, theright axle hub 88R and is corresponding right axle shaft 36R arepermitted to rotate relative to the right clutch actuator 90R to allowthe right wheel 24R to rotate faster in a forward direction than theleft wheel 24L. Contact between the stop posts 124 and the second stopsurfaces 130 limit relative rotation between the right clutch actuator90R and the left clutch actuator 90L to prevent the second ramp surfaces116 of the right clutch actuator 90R from engaging the cross-shaft 52 asthe right wheel 24R rotates at a higher forward speed than the leftwheel 24L. Rotation of the right clutch actuator 90R relative to theleft clutch actuator 90L stops when the neutral position 112 of theright clutch actuator 90R aligns with the cross-shaft 52. With the rightclutch 94R disengaged, contact between the cross-shaft 52 and the firstramp surfaces 114 of the left clutch actuator 90L continues such thatthe left clutch pack 94L remains actuated by force 300 such that torquecontinues to be transferred to the left axle shaft 36L.

FIG. 37 shows the differential 22 in a condition where the differentialcase 26 is being rotated in a reverse rotational direction and thevehicle is being driven straight. In this condition, the cross-shaft 52engages the second ramp surfaces 116 causing the left and right clutchactuators 90L, 90R to be forced axially outwardly to actuate the leftand right clutch packs 94L, 94R via forces 300. With the left and rightclutch packs 94L, 94R actuated, reverse torque is transferred equally tothe left and right axle hubs 88L, 88R, and their corresponding left andright axle shafts 36L, 36R thereby causing the left and right wheels24L, 24R to be driven rearwardly at the same speed. As shown at FIG. 37,while the wheels 24L, 24R are being driven rearwardly at the same speedby torque transferred through the differential 22, the stop posts 124are centered between the stop surfaces 128, 130. While the vehicle isbeing driven in the reverse direction, it will be appreciated that thedifferential 22 can accommodate over speed of the left and right wheelsin the same manner described with respect to the forward direction.

For assembly purposes, the main assembly 50 of the torque transferarrangement 28 is moveable between an axially extended configuration(see FIG. 31) and an axially compressed configuration (see FIG. 38). Theaxially extended configuration corresponds with the configuration of themain assembly 50 of the torque transfer arrangement 28 when the torquetransfer arrangement 28 is installed within the differential case 26 andthe cross-shaft 52 has been inserted within the shaft receptacle 58 ofthe main assembly 50 of the differential torque transfer arrangement 28.The main assembly 50 of the differential torque transfer arrangement 28has a configuration that allows the main assembly 50 to be moved to theaxially compressed configuration of FIG. 38 when the cross-shaft 52 isnot present within the shaft receptacle 58. For example, as shown atFIG. 31, first spacings S1 are defined between a shoulder 200 of eachclutch actuator 90 and an opposing shoulder 202 of each axle hub 88; asecond spacing S2 is defined between the inboard sides 102 of the clutchactuators 90; and third spacings S3 are defined between inboard sides205 of the inboard thrust washers 92 and opposing shoulders 203 of theactuators 90. With the cross-shaft 52 is removed from the shaftreceptacle 58, the main assembly 50 can be axially compressed by slidingthe axle hubs 88 inwardly relative to the clutch actuators 90 to take upthe spacings S1, by sliding clutch actuators 90 together to take up thespacing S2 and by sliding the clutch packs 94 and thrust washers 92, 96inwardly against the bias of the pre-load springs 100 to take-up thespacings S3.

FIG. 38 shows the differential 22 in the axially compressedconfiguration. In the axially compressed configuration, the mainassembly 50 of the torque transfer arrangement 28 has an axial length L1that is smaller than a corresponding primary axial length L2 (see FIG.10) of the main side openings 54 of the differential case 26. With themain assembly 50 of the differential torque transfer arrangement 28 inthe axially compressed configuration of FIG. 38, the main assembly 50can be inserted laterally into the interior of the differential case 26through one of the main side openings 54. Once the main assembly 50 hasbeen loaded into the interior of the differential case 26, the shaftreceptacle 58 of the main assembly 50 can be aligned with the shaftopenings 56 of the differential case 26 and the cross-shaft 52 can beinserted through the shaft openings 56 and the shaft receptacle 58. Asthe cross-shaft 52 is inserted into the shaft receptacle 58, the axlehubs 88 are forced axially outwardly to open the spacings S1 and theclutch actuators 90 are forced apart to open the spacing S2. Thus,insertion of the cross-shaft 52 through the shaft receptacle 58 movesthe main assembly 50 of the differential torque transfer arrangement 28from the axially compressed configuration of FIG. 38 to the axiallyexpanded configuration of FIGS. 30 and 31. It will be appreciated that afixture or other handling tool can be used to hold the main assembly 50in the axially compressed configuration of FIG. 38 while the mainassembly 50 is loaded into the differential case 26. Once the mainassembly 50 is released from the fixture within the differential case26, spring load from the pre-load springs 100 can force the clutch packs94 and thrust washers 92, 96 in outboard direction to open the spacingsS3.

As shown at FIG. 12, with the main assembly 50 in the axially extendedorientation, outboard ends 218 of the axle hubs 88 fit within the leftand right pockets 78L, 78R of the differential case 26 such that themain assembly 50 is captured within the differential case 26. Theoutboard ends 218 include outer bearing surfaces 220 that engagecorresponding cylindrical surfaces 222 of the pockets 78. The outerbearing surfaces 220 define outer bearing diameters BD of the axle hubs88. Additionally, the left and right outboard thrust washers 96L, 96Rabut against the left and right stops 79L, 79R such that the compressionload of the outboard springs 98 and the clutch pre-load of the springs100 are applied against the differential case 26 through the outboardthrust washers 96. Thus, once assembled, the clutch packs 94 can beeffectively axially compressed between clutch actuators 90 and thedifferential case 26. Also, the outboard springs 98 are axiallycompressed between clutch actuators 90 and the tabs of the outboardwashers 98 that bear against the differential case 26. The assembly ofthe differential 22 is completed by inserting the locking pin 60 inplace to prevent the cross-shaft 52 from disengaging from the shaftopenings 56.

The outer bearing diameters BD of the axle hubs 88 are larger than theinner diameters defined by the inner splines 186 of the of the secondclutch plates 164. As shown at FIGS. 25 and 26, serrations 224 (i.e.,receptacles, notches, spline receivers, etc.) are defined within theouter bearing surfaces 220 in alignment with the valleys of the outersplines 184 of the axle hubs 88. When the main assembly 50 is moved tothe axially compressed orientation, the teeth of the inner splines 184of at least some of the second clutch plates 164 slide axially intocorresponding serrations 224 defined at adjacent the bearing surfaces220. In this way, the serrations 224 provide a keying function formaintaining rotational alignment between the teeth of the inner splines186 and the valleys of their corresponding outer splines 184 when themain assembly is in the axially compressed orientation. Thus, because ofthis keying function, the inner splines 186 readily mate with theircorresponding outer splines 184 when the main assembly 50 is moved fromthe axially compressed orientation back to the axially extendedorientation. Maintaining rotational alignment of the splines 184, 186 issignificant because once pre-load is applied to the clutch packs 94,providing relative rotation between the clutch plates 162, 164 would bedifficult and could cause damage to the clutch plates 162, 164. In otherembodiments, the clutch plates can have main splines defining an innerdiameter larger than the outer diameter of the bearing surfaces, and alimited number (e.g., three) of keying splines defining an innerdiameter smaller than the outer diameter of the bearing surfaces. Thekeying splines can fit within keying receptacles defined within thebearing surfaces when the differential is collapsed to maintainrotational alignment of the clutch plates relative to the main splines.Because a reduced number of keying splines is provided, the amount thebearing surfaces are interrupted by the keying receptacles is reducedthereby providing a greater bearing surface area.

Various modifications and alterations of this disclosure will becomeapparent to those skilled in the art without departing from the scopeand spirit of this disclosure, and it should be understood that thescope of this disclosure is not to be unduly limited to the illustrativeexamples set forth herein.

What is claimed is:
 1. A differential comprising: a differential caseadapted to be rotated about an axis of rotation; a cross-shaftoperatively coupled to the differential case such that the cross-shaftand the differential case rotate together about the axis of rotation;left and right clutch actuators having opposing inboard sides betweenwhich the cross-shaft is positioned; left and right axle hubs positionedon opposite sides of the cross-shaft; a left clutch pack that preventsrelative rotation between the left clutch actuator and the left axle hubabout the axis of rotation when a left clutch engagement pressure isapplied to the left clutch pack; a right clutch pack that preventsrelative rotation between the right clutch actuator and the right axlehub about the axis of rotation when a right clutch engagement pressureis applied to the right clutch pack; a clutch pre-load spring thatapplies pressure to both the left and right clutch packs withoutapplying pressure to the left and right clutch actuators, the clutchpre-load spring being positioned inboard of the left and right clutchpacks; and wherein contact between the cross-shaft and a ramp surface atthe inboard side of the left clutch actuator causes the left clutchengagement pressure to be applied to the left clutch pack, and whereincontact between the cross-shaft and a ramp surface at the inboard sideof the right clutch actuator causes the right clutch engagement pressureto be applied to the right clutch pack.
 2. The differential of claim 1,wherein a central reference plane extends along an interface between theinboard sides of the left and right clutch actuators, wherein thecentral reference plane is perpendicular with respect to the axis ofrotation, and wherein the clutch pre-load spring extends across thecentral reference plane.
 3. The differential of claim 2, wherein alimited range of rotational movement about the axis of rotation ispermitted between the left and right clutch actuators, and wherein theclutch pre-load spring flexes in response to relative rotation betweenthe left and right clutch actuators about the axis of rotation.
 4. Thedifferential of claim 3, wherein the clutch pre-load spring is a coilspring.
 5. The differential of claim 4, wherein the inboard sides of theleft and right clutch actuators define pockets that cooperate to definea shaft receptacle that receives the cross-shaft, and wherein eachpocket includes first and second ramp surfaces separated by a neutralposition, wherein the left engagement pressure is not applied to theleft clutch pack when the cross-shaft aligns with the neutral positionof the left clutch actuator, and wherein the right engagement pressureis not applied to the right clutch pack when the cross-shaft aligns withthe neutral position of the right clutch actuator.
 6. The differentialof claim 5, further comprising a plurality of the clutch pre-loadsprings that cooperate to apply left and right clutch pre-loadsrespectively to the left and right clutch packs, wherein each of theclutch pre-load springs applies a portion of the left clutch pre-loadand a portion of the right clutch pre-load, and wherein none of theclutch pre-load springs apply pressure to the left and right actuators.7. The differential of claim 6, wherein the clutch pre-load springs arespaced uniformly about the axis of rotation.
 8. The differential ofclaim 6, wherein the left and right clutch actuators define a pluralityof spring holes each having open inboard and outboard ends, and whereineach of the clutch pre-load springs extends though one of the springholes of the left clutch actuator and a corresponding one of the springbores of the right clutch actuator.
 9. The differential of claim 1,further comprising a plurality of the clutch pre-load springs thatcooperate to apply left and right clutch pre-loads respectively to theleft and right clutch packs, wherein each of the clutch pre-load springsapplies a portion of the left clutch pre-load and a portion of the rightclutch pre-load without applying the pre-loads through the left andright clutch actuators.
 10. The differential of claim 9, wherein theclutch pre-load springs are spaced uniformly about the axis of rotation.11. The differential of claim 1, wherein the left and right clutchactuators define through-holes that receive the clutch pre-load springs.12. The differential of claim 11, wherein the through-holes each includecylindrical portions and tapered portions, wherein the tapered portionsdefine diameters that increase in size as the tapered portions extend inan inboard direction, and wherein major diameters of the taperedportions are positioned at the inboard sides of the left and rightclutch actuators.
 13. The differential of claim 9, wherein the left andright clutch actuators respectively house the left and right clutchpacks, wherein the clutch pre-load springs extend through the left andright clutch actuators and across an interface between the left andright clutch actuators, and wherein each of the clutch pre-load springsincludes opposite ends that abut against inboard thrust washers of theleft and right clutch packs.
 14. The differential of claim 1, furthercomprising outboard springs that bias the left and right clutchactuators toward one another without applying spring load through theleft and right clutch packs.
 15. A differential comprising: adifferential case adapted to be rotated about an axis of rotation; across-shaft operatively coupled to the differential case such that thecross-shaft and the differential case rotate together about the axis ofrotation, the cross-shaft being transversely aligned relative to theaxis of rotation; left and right clutch actuators having opposinginboard sides between which the cross-shaft is positioned, the inboardsides of the left and right clutch actuators defining pockets thatcooperate to define a shaft receptacle that receives the cross-shaft,each pocket including first and second ramp surfaces separated by aneutral position, the left and right clutch actuators defining springthrough-holes each having open inboard and outboard ends; left and rightaxle hubs positioned on opposite sides of the cross-shaft; a left clutchpack that prevents relative rotation between the left clutch actuatorand the left axle hub about the axis of rotation when a left clutchengagement pressure is applied to the left clutch pack; a right clutchpack that prevents relative rotation between the right clutch actuatorand the right axle hub about the axis of rotation when a right clutchengagement pressure is applied to the right clutch pack; clutch pre-loadsprings that each apply pre-load pressure to both the left and rightclutch packs, the clutch pre-load springs being positioned inboard ofthe left and right clutch packs and having a left portions positioned inthe spring through-holes of the left clutch actuator and right portionspositioned in the spring through holes of the right clutch actuator, theclutch pre-load springs extending across an interface between the leftand right clutch actuators; and wherein contact between the cross-shaftand one of the first and second ramp surfaces of the left clutchactuator causes the left clutch engagement pressure to be applied to theleft clutch pack, wherein contact between the cross-shaft and one of thefirst and second ramp surfaces of the right clutch actuator causes theright clutch engagement pressure to be applied to the right clutch pack,wherein the left engagement pressure is not applied to the left clutchpack when the cross-shaft aligns with the neutral position of the leftclutch actuator, and wherein the right engagement pressure is notapplied to the right clutch pack when the cross-shaft aligns with theneutral position of the right clutch actuator.
 16. The differential ofclaim 15, wherein the spring through-holes each have cylindricalportions adjacent the outboard ends and tapered portions adjacent theinboard ends, and wherein the tapered portions have major diameters atthe inboard sides of the left and right clutch actuators.
 17. Thedifferential of claim 16, wherein the pre-load springs each haveopposite ends that bias against inboard thrust washers of the left andright clutch packs.
 18. The differential of claim 15, further comprisingoutboard springs that bias the left and right clutch actuators towardone another without applying spring load through the left and rightclutch packs.
 19. A differential comprising: a differential case adaptedto be rotated about an axis of rotation; a cross-shaft operativelycoupled to the differential case such that the cross-shaft and thedifferential case rotate together about the axis of rotation, thecross-shaft being transversely aligned relative to the axis of rotation;left and right clutch housings having opposing inboard sides betweenwhich the cross-shaft is positioned, the inboard sides of the left andright clutch housings defining pockets that cooperate to define a shaftreceptacle that receives the cross-shaft, each pocket including firstand second ramp surfaces that are angled relative to one another so asto converge toward a neutral position located between the first andsecond ramp surfaces, the left and right clutch housings defining springthrough-holes each having open inboard and outboard ends; left and rightaxle hubs positioned on opposite sides of the cross-shaft, the left andright axle hubs being co-axially aligned along the axis of rotation; aleft clutch pack housed at least partially within the left clutchhousing and a right clutch pack that is housed at least partially withinthe right clutch housing, the left and right clutch packs each includingfirst clutch plates that are interleaved within respect to second clutchplates, the first clutch plates of the left clutch pack being carriedwith the left clutch housing and the second clutch plates of the leftclutch pack being carried with the left axle hub, wherein relativerotation about the axis of rotation is prevented between the left clutchhousing and the left axle hub when a left clutch engagement pressure isapplied to the left clutch pack, wherein relative rotation about theaxis of rotation is permitted between the left clutch housing and theleft axle hub when only a left clutch pre-load pressure is applied tothe left clutch pack, the first clutch plates of the right clutch packbeing carried with the right clutch housing and the second clutch platesof the right clutch pack being carried with the right axle hub, whereinrelative rotation about the axis of rotation is prevented between theright clutch housing and the right axle hub when a right clutchengagement pressure is applied to the right clutch pack, and whereinrelative rotation about the axis of rotation is permitted between theright clutch housing and the right axle hub when only a right clutchpre-load pressure is applied to the right clutch pack; a plurality ofclutch pre-load springs that cooperate to apply the left and rightpre-load pressures to the left and right clutch packs, the clutchpre-load springs being positioned inboard of the left and right clutchpacks and each having a left portion positioned within one of the springthrough-holes of the left clutch housing and a right portion positionedwithin one of the spring through-holes of the right clutch housing, eachof the clutch pre-load springs being configured to apply a portion ofthe left pre-load pressure to the left clutch pack and a portion of theright pre-load pressure to the right clutch pack; and wherein contactbetween the cross-shaft and one of the first and second ramp surfaces ofthe left clutch housing causes the left clutch engagement pressure to beapplied to the left clutch pack, wherein contact between the cross-shaftand one of the first and second ramp surfaces of the right clutchhousing causes the right clutch engagement pressure to be applied to theright clutch pack, wherein the left engagement pressure is not appliedto the left clutch pack when the cross-shaft aligns with the neutralposition of the left clutch housing, and wherein the right engagementpressure is not applied to the right clutch pack when the cross-shaftaligns with the neutral position of the right clutch housing.
 20. Thedifferential of claim 19, wherein the spring through-holes each havecylindrical portions adjacent the outboard ends and tapered portionsadjacent the inboard ends, and wherein the tapered portions have majordiameters at the inboard sides of the left and right clutch housings.